String.Split Method

Definition

Returns a string array that contains the substrings in this instance that are delimited by elements of a specified string or Unicode character array.

Overloads

Split(Char[], Int32, StringSplitOptions)

Splits a string into a maximum number of substrings based on specified delimiting characters and, optionally, options.

Split(Char, Int32, StringSplitOptions)

Splits a string into a maximum number of substrings based on a specified delimiting character and, optionally, options. Splits a string into a maximum number of substrings based on the provided character separator, optionally omitting empty substrings from the result.

Split(String[], Int32, StringSplitOptions)

Splits a string into a maximum number of substrings based on specified delimiting strings and, optionally, options.

Split(String[], StringSplitOptions)

Splits a string into substrings based on a specified delimiting string and, optionally, options.

Split(String, Int32, StringSplitOptions)

Splits a string into a maximum number of substrings based on a specified delimiting string and, optionally, options.

Split(Char[], StringSplitOptions)

Splits a string into substrings based on specified delimiting characters and options.

Split(Char[], Int32)

Splits a string into a maximum number of substrings based on specified delimiting characters.

Split(Char, StringSplitOptions)

Splits a string into substrings based on a specified delimiting character and, optionally, options.

Split(String, StringSplitOptions)

Splits a string into substrings that are based on the provided string separator.

Split(Char[])

Splits a string into substrings based on specified delimiting characters.

Remarks

Split is used to break a delimited string into substrings. You can use either a character array or a string array to specify zero or more delimiting characters or strings. If no delimiting characters are specified, the string is split at white-space characters.

Overloads of the Split method allow you to limit the number of substrings returned by the method (the Split(Char[], Int32) method), to specify whether to include empty strings and/or trim substrings in the result (the Split(Char[], StringSplitOptions) and Split(String[], StringSplitOptions) methods), or to do both (the Split(Char[], Int32, StringSplitOptions) and Split(String[], Int32, StringSplitOptions) methods).

Tip

The Split method is not always the best way to break a delimited string into substrings. If you don't want to extract all of the substrings of a delimited string, or if you want to parse a string based on a pattern instead of a set of delimiter characters, consider using regular expressions, or combine one of the search methods that returns the index of a character with the Substring method. For more information, see Extract substrings from a string.

Example

The following examples show three different overloads of String.Split(). The first example calls the Split(Char[]) overload and passes in a single delimiter.

string s = "You win some. You lose some.";

string[] subs = s.Split(' ');

foreach (var sub in subs)
{
    Console.WriteLine($"Substring: {sub}");
}

// This example produces the following output:
//
// Substring: You
// Substring: win
// Substring: some.
// Substring: You
// Substring: lose
// Substring: some.
Dim s As String = "You win some. You lose some."
Dim subs As String() = s.Split()

For Each substring As String In subs
    Console.WriteLine($"Substring: {substring}")
Next

' This example produces the following output:
'
' Substring: You
' Substring: win
' Substring: some.
' Substring: You
' Substring: lose
' Substring: some.

As you can see, the period characters (.) are included in two of the substrings. If you want to exclude the period characters, you can add the period character as an additional delimiting character. The next example shows how to do this.

string s = "You win some. You lose some.";

string[] subs = s.Split(' ', '.');

foreach (var sub in subs)
{
    Console.WriteLine($"Substring: {sub}");
}

// This example produces the following output:
//
// Substring: You
// Substring: win
// Substring: some
// Substring:
// Substring: You
// Substring: lose
// Substring: some
// Substring:
Dim s As String = "You win some. You lose some."
Dim subs As String() = s.Split(" "c, "."c)

For Each substring As String In subs
    Console.WriteLine($"Substring: {substring}")
Next

' This example produces the following output:
'
' Substring: You
' Substring: win
' Substring: some
' Substring:
' Substring: You
' Substring: lose
' Substring: some
' Substring:

The periods are gone from the substrings, but now two extra empty substrings have been included. These empty substring represent the substring between a word and the period that follows it. To omit empty substrings from the resulting array, you can call the Split(Char[], StringSplitOptions) overload and specify StringSplitOptions.RemoveEmptyEntries for the options parameter.

string s = "You win some. You lose some.";
char[] separators = new char[] { ' ', '.' };

string[] subs = s.Split(separators, StringSplitOptions.RemoveEmptyEntries);

foreach (var sub in subs)
{
    Console.WriteLine($"Substring: {sub}");
}

// This example produces the following output:
//
// Substring: You
// Substring: win
// Substring: some
// Substring: You
// Substring: lose
// Substring: some
Dim s As String = "You win some. You lose some."
Dim separators As Char() = New Char() {" "c, "."c}
Dim subs As String() = s.Split(separators, StringSplitOptions.RemoveEmptyEntries)

For Each substring As String In subs
    Console.WriteLine($"Substring: {substring}")
Next

' This example produces the following output:
'
' Substring: You
' Substring: win
' Substring: some
' Substring: You
' Substring: lose
' Substring: some

The sections for the individual overloads of String.Split() contain further examples.

Split(Char[], Int32, StringSplitOptions)

Splits a string into a maximum number of substrings based on specified delimiting characters and, optionally, options.

public:
 cli::array <System::String ^> ^ Split(cli::array <char> ^ separator, int count, StringSplitOptions options);
public string[] Split (char[] separator, int count, StringSplitOptions options);
public string[] Split (char[]? separator, int count, StringSplitOptions options);
[System.Runtime.InteropServices.ComVisible(false)]
public string[] Split (char[] separator, int count, StringSplitOptions options);
member this.Split : char[] * int * StringSplitOptions -> string[]
[<System.Runtime.InteropServices.ComVisible(false)>]
member this.Split : char[] * int * StringSplitOptions -> string[]
Public Function Split (separator As Char(), count As Integer, options As StringSplitOptions) As String()

Parameters

separator
Char[]

An array of characters that delimit the substrings in this string, an empty array that contains no delimiters, or null.

count
Int32

The maximum number of substrings to return.

options
StringSplitOptions

A bitwise combination of the enumeration values that specifies whether to trim substrings and include empty substrings.

Returns

String[]

An array that contains the substrings in this string that are delimited by one or more characters in separator. For more information, see the Remarks section.

Attributes

Exceptions

count is negative.

options is not one of the StringSplitOptions values.

Examples

The following example uses the StringSplitOptions enumeration to include or exclude substrings generated by the Split method.

// This example demonstrates the String.Split(Char[], Boolean) and 
//                               String.Split(Char[], Int32, Boolean) methods
using namespace System;
void Show( array<String^>^entries )
{
   Console::WriteLine( "The return value contains these {0} elements:", entries->Length );
   System::Collections::IEnumerator^ myEnum = entries->GetEnumerator();
   while ( myEnum->MoveNext() )
   {
      String^ entry = safe_cast<String^>(myEnum->Current);
      Console::Write( "<{0}>", entry );
   }

   Console::Write( "{0}{0}", Environment::NewLine );
}

int main()
{
   String^ s = ",one,,,two,,,,,three,,";
   array<Char>^sep = gcnew array<Char>{
      ','
   };
   array<String^>^result;
   
   //
   Console::WriteLine( "The original string is \"{0}\".", s );
   Console::WriteLine( "The separation character is '{0}'.", sep[ 0 ] );
   Console::WriteLine();
   
   //
   Console::WriteLine( "Split the string and return all elements:" );
   result = s->Split( sep, StringSplitOptions::None );
   Show( result );
   
   //
   Console::WriteLine( "Split the string and return all non-empty elements:" );
   result = s->Split( sep, StringSplitOptions::RemoveEmptyEntries );
   Show( result );
   
   //
   Console::WriteLine( "Split the string and return 2 elements:" );
   result = s->Split( sep, 2, StringSplitOptions::None );
   Show( result );
   
   //
   Console::WriteLine( "Split the string and return 2 non-empty elements:" );
   result = s->Split( sep, 2, StringSplitOptions::RemoveEmptyEntries );
   Show( result );
}

/*
This example produces the following results:

The original string is ",one,,,two,,,,,three,,".
The separation character is ','.

Split the string and return all elements:
The return value contains these 12 elements:
<><one><><><two><><><><><three><><>

Split the string and return all non-empty elements:
The return value contains these 3 elements:
<one><two><three>

Split the string and return 2 elements:
The return value contains these 2 elements:
<><one,,,two,,,,,three,,>

Split the string and return 2 non-empty elements:
The return value contains these 2 elements:
<one><,,two,,,,,three,,>

*/
// This example demonstrates the String.Split() methods that use
// the StringSplitOptions enumeration.
string s1 = ",ONE,,TWO,,,THREE,,";
string s2 = "[stop]" +
            "ONE[stop][stop]" +
            "TWO[stop][stop][stop]" +
            "THREE[stop][stop]";
char[] charSeparators = new char[] { ',' };
string[] stringSeparators = new string[] { "[stop]" };
string[] result;
// ------------------------------------------------------------------------------
// Split a string delimited by characters.
// ------------------------------------------------------------------------------
Console.WriteLine("1) Split a string delimited by characters:\n");

// Display the original string and delimiter characters.
Console.WriteLine($"1a) The original string is \"{s1}\".");
Console.WriteLine($"The delimiter character is '{charSeparators[0]}'.\n");

// Split a string delimited by characters and return all elements.
Console.WriteLine("1b) Split a string delimited by characters and " +
                  "return all elements:");
result = s1.Split(charSeparators, StringSplitOptions.None);
Show(result);

// Split a string delimited by characters and return all non-empty elements.
Console.WriteLine("1c) Split a string delimited by characters and " +
                  "return all non-empty elements:");
result = s1.Split(charSeparators, StringSplitOptions.RemoveEmptyEntries);
Show(result);

// Split the original string into the string and empty string before the
// delimiter and the remainder of the original string after the delimiter.
Console.WriteLine("1d) Split a string delimited by characters and " +
                  "return 2 elements:");
result = s1.Split(charSeparators, 2, StringSplitOptions.None);
Show(result);

// Split the original string into the string after the delimiter and the
// remainder of the original string after the delimiter.
Console.WriteLine("1e) Split a string delimited by characters and " +
                  "return 2 non-empty elements:");
result = s1.Split(charSeparators, 2, StringSplitOptions.RemoveEmptyEntries);
Show(result);

// ------------------------------------------------------------------------------
// Split a string delimited by another string.
// ------------------------------------------------------------------------------
Console.WriteLine("2) Split a string delimited by another string:\n");

// Display the original string and delimiter string.
Console.WriteLine($"2a) The original string is \"{s2}\".");
Console.WriteLine($"The delimiter string is \"{stringSeparators[0]}\".\n");

// Split a string delimited by another string and return all elements.
Console.WriteLine("2b) Split a string delimited by another string and " +
                  "return all elements:");
result = s2.Split(stringSeparators, StringSplitOptions.None);
Show(result);

// Split the original string at the delimiter and return all non-empty elements.
Console.WriteLine("2c) Split a string delimited by another string and " +
                  "return all non-empty elements:");
result = s2.Split(stringSeparators, StringSplitOptions.RemoveEmptyEntries);
Show(result);

// Split the original string into the empty string before the
// delimiter and the remainder of the original string after the delimiter.
Console.WriteLine("2d) Split a string delimited by another string and " +
                  "return 2 elements:");
result = s2.Split(stringSeparators, 2, StringSplitOptions.None);
Show(result);

// Split the original string into the string after the delimiter and the
// remainder of the original string after the delimiter.
Console.WriteLine("2e) Split a string delimited by another string and " +
                  "return 2 non-empty elements:");
result = s2.Split(stringSeparators, 2, StringSplitOptions.RemoveEmptyEntries);
Show(result);

// Display the array of separated strings using a local function
void Show(string[] entries)
{
    Console.WriteLine($"The return value contains these {entries.Length} elements:");
    foreach (string entry in entries)
    {
        Console.Write($"<{entry}>");
    }
    Console.Write("\n\n");
}

/*
This example produces the following results:

1) Split a string delimited by characters:

1a) The original string is ",ONE,,TWO,,,THREE,,".
The delimiter character is ','.

1b) Split a string delimited by characters and return all elements:
The return value contains these 9 elements:
<><ONE><><TWO><><><THREE><><>

1c) Split a string delimited by characters and return all non-empty elements:
The return value contains these 3 elements:
<ONE><TWO><THREE>

1d) Split a string delimited by characters and return 2 elements:
The return value contains these 2 elements:
<><ONE,,TWO,,,THREE,,>

1e) Split a string delimited by characters and return 2 non-empty elements:
The return value contains these 2 elements:
<ONE><TWO,,,THREE,,>

2) Split a string delimited by another string:

2a) The original string is "[stop]ONE[stop][stop]TWO[stop][stop][stop]THREE[stop][stop]".
The delimiter string is "[stop]".

2b) Split a string delimited by another string and return all elements:
The return value contains these 9 elements:
<><ONE><><TWO><><><THREE><><>

2c) Split a string delimited by another string and return all non-empty elements:
The return value contains these 3 elements:
<ONE><TWO><THREE>

2d) Split a string delimited by another string and return 2 elements:
The return value contains these 2 elements:
<><ONE[stop][stop]TWO[stop][stop][stop]THREE[stop][stop]>

2e) Split a string delimited by another string and return 2 non-empty elements:
The return value contains these 2 elements:
<ONE><TWO[stop][stop][stop]THREE[stop][stop]>

*/
    Dim s1 As String = ",ONE,,TWO,,,THREE,,"
    Dim s2 As String = "[stop]" &
                       "ONE[stop][stop]" &
                       "TWO[stop][stop][stop]" &
                       "THREE[stop][stop]"
    Dim charSeparators() As Char = {","c}
    Dim stringSeparators() As String = {"[stop]"}
    Dim result() As String
    ' ------------------------------------------------------------------------------
    ' Split a string delimited by characters.
    ' ------------------------------------------------------------------------------
    Console.WriteLine("1) Split a string delimited by characters:" & vbCrLf)

    ' Display the original string and delimiter characters.
    Console.WriteLine("1a) The original string is ""{0}"".", s1)
    Console.WriteLine("The delimiter character is '{0}'." & vbCrLf, charSeparators(0))

    ' Split a string delimited by characters and return all elements.
    Console.WriteLine("1b) Split a string delimited by characters and " &
                      "return all elements:")
    result = s1.Split(charSeparators, StringSplitOptions.None)
    Show(result)

    ' Split a string delimited by characters and return all non-empty elements.
    Console.WriteLine("1c) Split a string delimited by characters and " &
                      "return all non-empty elements:")
    result = s1.Split(charSeparators, StringSplitOptions.RemoveEmptyEntries)
    Show(result)

    ' Split the original string into the string and empty string before the 
    ' delimiter and the remainder of the original string after the delimiter.
    Console.WriteLine("1d) Split a string delimited by characters and " &
                      "return 2 elements:")
    result = s1.Split(charSeparators, 2, StringSplitOptions.None)
    Show(result)

    ' Split the original string into the string after the delimiter and the 
    ' remainder of the original string after the delimiter.
    Console.WriteLine("1e) Split a string delimited by characters and " &
                      "return 2 non-empty elements:")
    result = s1.Split(charSeparators, 2, StringSplitOptions.RemoveEmptyEntries)
    Show(result)

    ' ------------------------------------------------------------------------------
    ' Split a string delimited by another string.
    ' ------------------------------------------------------------------------------
    Console.WriteLine("2) Split a string delimited by another string:" & vbCrLf)

    ' Display the original string and delimiter string.
    Console.WriteLine("2a) The original string is ""{0}"".", s2)
    Console.WriteLine("The delimiter string is ""{0}""." & vbCrLf, stringSeparators(0))

    ' Split a string delimited by another string and return all elements.
    Console.WriteLine("2b) Split a string delimited by another string and " &
                      "return all elements:")
    result = s2.Split(stringSeparators, StringSplitOptions.None)
    Show(result)

    ' Split the original string at the delimiter and return all non-empty elements.
    Console.WriteLine("2c) Split a string delimited by another string and " &
                      "return all non-empty elements:")
    result = s2.Split(stringSeparators, StringSplitOptions.RemoveEmptyEntries)
    Show(result)

    ' Split the original string into the empty string before the 
    ' delimiter and the remainder of the original string after the delimiter.
    Console.WriteLine("2d) Split a string delimited by another string and " &
                      "return 2 elements:")
    result = s2.Split(stringSeparators, 2, StringSplitOptions.None)
    Show(result)

    ' Split the original string into the string after the delimiter and the 
    ' remainder of the original string after the delimiter.
    Console.WriteLine("2e) Split a string delimited by another string and " &
                      "return 2 non-empty elements:")
    result = s2.Split(stringSeparators, 2, StringSplitOptions.RemoveEmptyEntries)
    Show(result)

End Sub


' Display the array of separated strings.
Public Shared Sub Show(ByVal entries() As String)
    Console.WriteLine("The return value contains these {0} elements:", entries.Length)
    Dim entry As String
    For Each entry In entries
        Console.Write("<{0}>", entry)
    Next entry
    Console.Write(vbCrLf & vbCrLf)

End Sub

'This example produces the following results:
'
'1) Split a string delimited by characters:
'
'1a) The original string is ",ONE,,TWO,,,THREE,,".
'The delimiter character is ','.
'
'1b) Split a string delimited by characters and return all elements:
'The return value contains these 9 elements:
'<><ONE><><TWO><><><THREE><><>
'
'1c) Split a string delimited by characters and return all non-empty elements:
'The return value contains these 3 elements:
'<ONE><TWO><THREE>
'
'1d) Split a string delimited by characters and return 2 elements:
'The return value contains these 2 elements:
'<><ONE,,TWO,,,THREE,,>
'
'1e) Split a string delimited by characters and return 2 non-empty elements:
'The return value contains these 2 elements:
'<ONE><TWO,,,THREE,,>
'
'2) Split a string delimited by another string:
'
'2a) The original string is "[stop]ONE[stop][stop]TWO[stop][stop][stop]THREE[stop][stop]".
'The delimiter string is "[stop]".
'
'2b) Split a string delimited by another string and return all elements:
'The return value contains these 9 elements:
'<><ONE><><TWO><><><THREE><><>
'
'2c) Split a string delimited by another string and return all non-empty elements:
'The return value contains these 3 elements:
'<ONE><TWO><THREE>
'
'2d) Split a string delimited by another string and return 2 elements:
'The return value contains these 2 elements:
'<><ONE[stop][stop]TWO[stop][stop][stop]THREE[stop][stop]>
'
'2e) Split a string delimited by another string and return 2 non-empty elements:
'The return value contains these 2 elements:
'<ONE><TWO[stop][stop][stop]THREE[stop][stop]>
'

Remarks

Delimiter characters are not included in the elements of the returned array.

If this instance does not contain any of the characters in separator, or the count parameter is 1, the returned array consists of a single element that contains this instance. If the separator parameter is null or contains no characters, white-space characters are assumed to be the delimiters. White-space characters are defined by the Unicode standard and the Char.IsWhiteSpace method returns true if they are passed to it. However, if the separator parameter in the call to this method overload is null, compiler overload resolution fails. To unambiguously identify the called method, your code must indicate the type of the null. The following example shows several ways to unambiguously identify this overload.

string phrase = "The quick  brown fox";

_ = phrase.Split(default(char[]), 3, StringSplitOptions.RemoveEmptyEntries);

_ = phrase.Split((char[])null, 3, StringSplitOptions.RemoveEmptyEntries);

_ = phrase.Split(null as char[], 3, StringSplitOptions.RemoveEmptyEntries);
Dim phrase As String = "The quick brown fox"
Dim words() As String

words = phrase.Split(TryCast(Nothing, Char()), 3,
                       StringSplitOptions.RemoveEmptyEntries)

words = phrase.Split(New Char() {}, 3,
                     StringSplitOptions.RemoveEmptyEntries)

If the count parameter is zero, or the options parameter is RemoveEmptyEntries and the length of this instance is zero, an empty array is returned.

Each element of separator defines a separate delimiter character. If the options parameter is None, and two delimiters are adjacent or a delimiter is found at the beginning or end of this instance, the corresponding array element contains Empty.

If there are more than count substrings in this instance, the first count minus 1 substrings are returned in the first count minus 1 elements of the return value, and the remaining characters in this instance are returned in the last element of the return value.

If count is greater than the number of substrings, the available substrings are returned and no exception is thrown.

Performance considerations

The Split methods allocate memory for the returned array object and a String object for each array element. If your application requires optimal performance or if managing memory allocation is critical in your application, consider using the IndexOf or IndexOfAny method, and optionally the Compare method, to locate a substring within a string.

If you are splitting a string at a separator character, use the IndexOf or IndexOfAny method to locate a separator character in the string. If you are splitting a string at a separator string, use the IndexOf or IndexOfAny method to locate the first character of the separator string. Then use the Compare method to determine whether the characters after that first character are equal to the remaining characters of the separator string.

In addition, if the same set of characters is used to split strings in multiple Split method calls, consider creating a single array and referencing it in each method call. This significantly reduces the additional overhead of each method call.

Notes to Callers

In .NET Framework 3.5 and earlier versions, if the Split(Char[]) method is passed a separator that is null or contains no characters, the method uses a slightly different set of white-space characters to split the string than the Trim(Char[]) method does to trim the string. Starting with .NET Framework 4, both methods use an identical set of Unicode white-space characters.

Applies to

Split(Char, Int32, StringSplitOptions)

Splits a string into a maximum number of substrings based on a specified delimiting character and, optionally, options. Splits a string into a maximum number of substrings based on the provided character separator, optionally omitting empty substrings from the result.

public string[] Split (char separator, int count, StringSplitOptions options = System.StringSplitOptions.None);
member this.Split : char * int * StringSplitOptions -> string[]
Public Function Split (separator As Char, count As Integer, Optional options As StringSplitOptions = System.StringSplitOptions.None) As String()

Parameters

separator
Char

A character that delimits the substrings in this instance.

count
Int32

The maximum number of elements expected in the array.

options
StringSplitOptions

A bitwise combination of the enumeration values that specifies whether to trim substrings and include empty substrings.

Returns

String[]

An array that contains at most count substrings from this instance that are delimited by separator.

Remarks

If the string has already been split count - 1 times, but the end of the string has not been reached, then the last string in the returned array will contain this instance's remaining trailing substring, untouched.

Applies to

Split(String[], Int32, StringSplitOptions)

Splits a string into a maximum number of substrings based on specified delimiting strings and, optionally, options.

public:
 cli::array <System::String ^> ^ Split(cli::array <System::String ^> ^ separator, int count, StringSplitOptions options);
public string[] Split (string[] separator, int count, StringSplitOptions options);
public string[] Split (string[]? separator, int count, StringSplitOptions options);
[System.Runtime.InteropServices.ComVisible(false)]
public string[] Split (string[] separator, int count, StringSplitOptions options);
member this.Split : string[] * int * StringSplitOptions -> string[]
[<System.Runtime.InteropServices.ComVisible(false)>]
member this.Split : string[] * int * StringSplitOptions -> string[]
Public Function Split (separator As String(), count As Integer, options As StringSplitOptions) As String()

Parameters

separator
String[]

The strings that delimit the substrings in this string, an empty array that contains no delimiters, or null.

count
Int32

The maximum number of substrings to return.

options
StringSplitOptions

A bitwise combination of the enumeration values that specifies whether to trim substrings and include empty substrings.

Returns

String[]

An array whose elements contain the substrings in this string that are delimited by one or more strings in separator. For more information, see the Remarks section.

Attributes

Exceptions

count is negative.

options is not one of the StringSplitOptions values.

Examples

The following example uses the StringSplitOptions enumeration to include or exclude substrings generated by the Split method.

// This example demonstrates the String.Split(Char[], Boolean) and 
//                               String.Split(Char[], Int32, Boolean) methods
using namespace System;
void Show( array<String^>^entries )
{
   Console::WriteLine( "The return value contains these {0} elements:", entries->Length );
   System::Collections::IEnumerator^ myEnum = entries->GetEnumerator();
   while ( myEnum->MoveNext() )
   {
      String^ entry = safe_cast<String^>(myEnum->Current);
      Console::Write( "<{0}>", entry );
   }

   Console::Write( "{0}{0}", Environment::NewLine );
}

int main()
{
   String^ s = ",one,,,two,,,,,three,,";
   array<Char>^sep = gcnew array<Char>{
      ','
   };
   array<String^>^result;
   
   //
   Console::WriteLine( "The original string is \"{0}\".", s );
   Console::WriteLine( "The separation character is '{0}'.", sep[ 0 ] );
   Console::WriteLine();
   
   //
   Console::WriteLine( "Split the string and return all elements:" );
   result = s->Split( sep, StringSplitOptions::None );
   Show( result );
   
   //
   Console::WriteLine( "Split the string and return all non-empty elements:" );
   result = s->Split( sep, StringSplitOptions::RemoveEmptyEntries );
   Show( result );
   
   //
   Console::WriteLine( "Split the string and return 2 elements:" );
   result = s->Split( sep, 2, StringSplitOptions::None );
   Show( result );
   
   //
   Console::WriteLine( "Split the string and return 2 non-empty elements:" );
   result = s->Split( sep, 2, StringSplitOptions::RemoveEmptyEntries );
   Show( result );
}

/*
This example produces the following results:

The original string is ",one,,,two,,,,,three,,".
The separation character is ','.

Split the string and return all elements:
The return value contains these 12 elements:
<><one><><><two><><><><><three><><>

Split the string and return all non-empty elements:
The return value contains these 3 elements:
<one><two><three>

Split the string and return 2 elements:
The return value contains these 2 elements:
<><one,,,two,,,,,three,,>

Split the string and return 2 non-empty elements:
The return value contains these 2 elements:
<one><,,two,,,,,three,,>

*/
// This example demonstrates the String.Split() methods that use
// the StringSplitOptions enumeration.
string s1 = ",ONE,,TWO,,,THREE,,";
string s2 = "[stop]" +
            "ONE[stop][stop]" +
            "TWO[stop][stop][stop]" +
            "THREE[stop][stop]";
char[] charSeparators = new char[] { ',' };
string[] stringSeparators = new string[] { "[stop]" };
string[] result;
// ------------------------------------------------------------------------------
// Split a string delimited by characters.
// ------------------------------------------------------------------------------
Console.WriteLine("1) Split a string delimited by characters:\n");

// Display the original string and delimiter characters.
Console.WriteLine($"1a) The original string is \"{s1}\".");
Console.WriteLine($"The delimiter character is '{charSeparators[0]}'.\n");

// Split a string delimited by characters and return all elements.
Console.WriteLine("1b) Split a string delimited by characters and " +
                  "return all elements:");
result = s1.Split(charSeparators, StringSplitOptions.None);
Show(result);

// Split a string delimited by characters and return all non-empty elements.
Console.WriteLine("1c) Split a string delimited by characters and " +
                  "return all non-empty elements:");
result = s1.Split(charSeparators, StringSplitOptions.RemoveEmptyEntries);
Show(result);

// Split the original string into the string and empty string before the
// delimiter and the remainder of the original string after the delimiter.
Console.WriteLine("1d) Split a string delimited by characters and " +
                  "return 2 elements:");
result = s1.Split(charSeparators, 2, StringSplitOptions.None);
Show(result);

// Split the original string into the string after the delimiter and the
// remainder of the original string after the delimiter.
Console.WriteLine("1e) Split a string delimited by characters and " +
                  "return 2 non-empty elements:");
result = s1.Split(charSeparators, 2, StringSplitOptions.RemoveEmptyEntries);
Show(result);

// ------------------------------------------------------------------------------
// Split a string delimited by another string.
// ------------------------------------------------------------------------------
Console.WriteLine("2) Split a string delimited by another string:\n");

// Display the original string and delimiter string.
Console.WriteLine($"2a) The original string is \"{s2}\".");
Console.WriteLine($"The delimiter string is \"{stringSeparators[0]}\".\n");

// Split a string delimited by another string and return all elements.
Console.WriteLine("2b) Split a string delimited by another string and " +
                  "return all elements:");
result = s2.Split(stringSeparators, StringSplitOptions.None);
Show(result);

// Split the original string at the delimiter and return all non-empty elements.
Console.WriteLine("2c) Split a string delimited by another string and " +
                  "return all non-empty elements:");
result = s2.Split(stringSeparators, StringSplitOptions.RemoveEmptyEntries);
Show(result);

// Split the original string into the empty string before the
// delimiter and the remainder of the original string after the delimiter.
Console.WriteLine("2d) Split a string delimited by another string and " +
                  "return 2 elements:");
result = s2.Split(stringSeparators, 2, StringSplitOptions.None);
Show(result);

// Split the original string into the string after the delimiter and the
// remainder of the original string after the delimiter.
Console.WriteLine("2e) Split a string delimited by another string and " +
                  "return 2 non-empty elements:");
result = s2.Split(stringSeparators, 2, StringSplitOptions.RemoveEmptyEntries);
Show(result);

// Display the array of separated strings using a local function
void Show(string[] entries)
{
    Console.WriteLine($"The return value contains these {entries.Length} elements:");
    foreach (string entry in entries)
    {
        Console.Write($"<{entry}>");
    }
    Console.Write("\n\n");
}

/*
This example produces the following results:

1) Split a string delimited by characters:

1a) The original string is ",ONE,,TWO,,,THREE,,".
The delimiter character is ','.

1b) Split a string delimited by characters and return all elements:
The return value contains these 9 elements:
<><ONE><><TWO><><><THREE><><>

1c) Split a string delimited by characters and return all non-empty elements:
The return value contains these 3 elements:
<ONE><TWO><THREE>

1d) Split a string delimited by characters and return 2 elements:
The return value contains these 2 elements:
<><ONE,,TWO,,,THREE,,>

1e) Split a string delimited by characters and return 2 non-empty elements:
The return value contains these 2 elements:
<ONE><TWO,,,THREE,,>

2) Split a string delimited by another string:

2a) The original string is "[stop]ONE[stop][stop]TWO[stop][stop][stop]THREE[stop][stop]".
The delimiter string is "[stop]".

2b) Split a string delimited by another string and return all elements:
The return value contains these 9 elements:
<><ONE><><TWO><><><THREE><><>

2c) Split a string delimited by another string and return all non-empty elements:
The return value contains these 3 elements:
<ONE><TWO><THREE>

2d) Split a string delimited by another string and return 2 elements:
The return value contains these 2 elements:
<><ONE[stop][stop]TWO[stop][stop][stop]THREE[stop][stop]>

2e) Split a string delimited by another string and return 2 non-empty elements:
The return value contains these 2 elements:
<ONE><TWO[stop][stop][stop]THREE[stop][stop]>

*/
    Dim s1 As String = ",ONE,,TWO,,,THREE,,"
    Dim s2 As String = "[stop]" &
                       "ONE[stop][stop]" &
                       "TWO[stop][stop][stop]" &
                       "THREE[stop][stop]"
    Dim charSeparators() As Char = {","c}
    Dim stringSeparators() As String = {"[stop]"}
    Dim result() As String
    ' ------------------------------------------------------------------------------
    ' Split a string delimited by characters.
    ' ------------------------------------------------------------------------------
    Console.WriteLine("1) Split a string delimited by characters:" & vbCrLf)

    ' Display the original string and delimiter characters.
    Console.WriteLine("1a) The original string is ""{0}"".", s1)
    Console.WriteLine("The delimiter character is '{0}'." & vbCrLf, charSeparators(0))

    ' Split a string delimited by characters and return all elements.
    Console.WriteLine("1b) Split a string delimited by characters and " &
                      "return all elements:")
    result = s1.Split(charSeparators, StringSplitOptions.None)
    Show(result)

    ' Split a string delimited by characters and return all non-empty elements.
    Console.WriteLine("1c) Split a string delimited by characters and " &
                      "return all non-empty elements:")
    result = s1.Split(charSeparators, StringSplitOptions.RemoveEmptyEntries)
    Show(result)

    ' Split the original string into the string and empty string before the 
    ' delimiter and the remainder of the original string after the delimiter.
    Console.WriteLine("1d) Split a string delimited by characters and " &
                      "return 2 elements:")
    result = s1.Split(charSeparators, 2, StringSplitOptions.None)
    Show(result)

    ' Split the original string into the string after the delimiter and the 
    ' remainder of the original string after the delimiter.
    Console.WriteLine("1e) Split a string delimited by characters and " &
                      "return 2 non-empty elements:")
    result = s1.Split(charSeparators, 2, StringSplitOptions.RemoveEmptyEntries)
    Show(result)

    ' ------------------------------------------------------------------------------
    ' Split a string delimited by another string.
    ' ------------------------------------------------------------------------------
    Console.WriteLine("2) Split a string delimited by another string:" & vbCrLf)

    ' Display the original string and delimiter string.
    Console.WriteLine("2a) The original string is ""{0}"".", s2)
    Console.WriteLine("The delimiter string is ""{0}""." & vbCrLf, stringSeparators(0))

    ' Split a string delimited by another string and return all elements.
    Console.WriteLine("2b) Split a string delimited by another string and " &
                      "return all elements:")
    result = s2.Split(stringSeparators, StringSplitOptions.None)
    Show(result)

    ' Split the original string at the delimiter and return all non-empty elements.
    Console.WriteLine("2c) Split a string delimited by another string and " &
                      "return all non-empty elements:")
    result = s2.Split(stringSeparators, StringSplitOptions.RemoveEmptyEntries)
    Show(result)

    ' Split the original string into the empty string before the 
    ' delimiter and the remainder of the original string after the delimiter.
    Console.WriteLine("2d) Split a string delimited by another string and " &
                      "return 2 elements:")
    result = s2.Split(stringSeparators, 2, StringSplitOptions.None)
    Show(result)

    ' Split the original string into the string after the delimiter and the 
    ' remainder of the original string after the delimiter.
    Console.WriteLine("2e) Split a string delimited by another string and " &
                      "return 2 non-empty elements:")
    result = s2.Split(stringSeparators, 2, StringSplitOptions.RemoveEmptyEntries)
    Show(result)

End Sub


' Display the array of separated strings.
Public Shared Sub Show(ByVal entries() As String)
    Console.WriteLine("The return value contains these {0} elements:", entries.Length)
    Dim entry As String
    For Each entry In entries
        Console.Write("<{0}>", entry)
    Next entry
    Console.Write(vbCrLf & vbCrLf)

End Sub

'This example produces the following results:
'
'1) Split a string delimited by characters:
'
'1a) The original string is ",ONE,,TWO,,,THREE,,".
'The delimiter character is ','.
'
'1b) Split a string delimited by characters and return all elements:
'The return value contains these 9 elements:
'<><ONE><><TWO><><><THREE><><>
'
'1c) Split a string delimited by characters and return all non-empty elements:
'The return value contains these 3 elements:
'<ONE><TWO><THREE>
'
'1d) Split a string delimited by characters and return 2 elements:
'The return value contains these 2 elements:
'<><ONE,,TWO,,,THREE,,>
'
'1e) Split a string delimited by characters and return 2 non-empty elements:
'The return value contains these 2 elements:
'<ONE><TWO,,,THREE,,>
'
'2) Split a string delimited by another string:
'
'2a) The original string is "[stop]ONE[stop][stop]TWO[stop][stop][stop]THREE[stop][stop]".
'The delimiter string is "[stop]".
'
'2b) Split a string delimited by another string and return all elements:
'The return value contains these 9 elements:
'<><ONE><><TWO><><><THREE><><>
'
'2c) Split a string delimited by another string and return all non-empty elements:
'The return value contains these 3 elements:
'<ONE><TWO><THREE>
'
'2d) Split a string delimited by another string and return 2 elements:
'The return value contains these 2 elements:
'<><ONE[stop][stop]TWO[stop][stop][stop]THREE[stop][stop]>
'
'2e) Split a string delimited by another string and return 2 non-empty elements:
'The return value contains these 2 elements:
'<ONE><TWO[stop][stop][stop]THREE[stop][stop]>
'

Remarks

Delimiter strings are not included in the elements of the returned array.

If this instance does not contain any of the strings in separator, or the count parameter is 1, the returned array consists of a single element that contains this instance. If the separator parameter is null or contains no characters, white-space characters are assumed to be the delimiters. White-space characters are defined by the Unicode standard and the Char.IsWhiteSpace method returns true if they are passed to it. However, if the separator parameter in the call to this method overload is null, compiler overload resolution fails. To unambiguously identify the called method, your code must indicate the type of the null. The following example shows several ways to unambiguously identify this overload.

string phrase = "The quick  brown fox";

_ = phrase.Split(default(string[]), 3, StringSplitOptions.RemoveEmptyEntries);

_ = phrase.Split((string[])null, 3, StringSplitOptions.RemoveEmptyEntries);

_ = phrase.Split(null as string[], 3, StringSplitOptions.RemoveEmptyEntries);
Dim phrase As String = "The quick brown fox"
Dim words() As String

words = phrase.Split(TryCast(Nothing, String()), 3,
                       StringSplitOptions.RemoveEmptyEntries)

words = phrase.Split(New String() {}, 3,
                     StringSplitOptions.RemoveEmptyEntries)

If the count parameter is zero, or the options parameter is RemoveEmptyEntries and the length of this instance is zero, an empty array is returned.

Each element of separator defines a separate delimiter that consists of one or more characters. If the options parameter is None, and two delimiters are adjacent or a delimiter is found at the beginning or end of this instance, the corresponding array element contains Empty.

If there are more than count substrings in this instance, the first count minus 1 substrings are returned in the first count minus 1 elements of the return value, and the remaining characters in this instance are returned in the last element of the return value.

If count is greater than the number of substrings, the available substrings are returned and no exception is thrown.

The separator array

If any of the elements in separator consists of multiple characters, the entire substring is considered a delimiter. For example, if one of the elements in separator is "10", attempting to split the string "This10is10a10string." returns this four-element array: { "This", "is", "a", "string." }.

Comparison details

The Split method extracts the substrings in this string that are delimited by one or more of the strings in the separator parameter, and returns those substrings as elements of an array.

The Split method looks for delimiters by performing comparisons using case-sensitive ordinal sort rules. For more information about word, string, and ordinal sorts, see the System.Globalization.CompareOptions enumeration.

The Split method ignores any element of separator whose value is null or the empty string ("").

To avoid ambiguous results when strings in separator have characters in common, the Split method proceeds from the beginning to the end of the value of the instance, and matches the first element in separator that is equal to a delimiter in the instance. The order in which substrings are encountered in the instance takes precedence over the order of elements in separator.

For example, consider an instance whose value is "abcdef". If the first element in separator was "ef" and the second element was "bcde", the result of the split operation would be "a" and "f". This is because the substring in the instance, "bcde", is encountered and matches an element in separator before the substring "f" is encountered.

However, if the first element of separator was "bcd" and the second element was "bc", the result of the split operation would be "a" and "ef". This is because "bcd" is the first delimiter in separator that matches a delimiter in the instance. If the order of the separators was reversed so the first element was "bc" and the second element was "bcd", the result would be "a" and "def".

Performance considerations

The Split methods allocate memory for the returned array object and a String object for each array element. If your application requires optimal performance or if managing memory allocation is critical in your application, consider using the IndexOf or IndexOfAny method, and optionally the Compare method, to locate a substring within a string.

If you are splitting a string at a separator character, use the IndexOf or IndexOfAny method to locate a separator character in the string. If you are splitting a string at a separator string, use the IndexOf or IndexOfAny method to locate the first character of the separator string. Then use the Compare method to determine whether the characters after that first character are equal to the remaining characters of the separator string.

In addition, if the same set of characters is used to split strings in multiple Split method calls, consider creating a single array and referencing it in each method call. This significantly reduces the additional overhead of each method call.

Notes to Callers

In .NET Framework 3.5 and earlier versions, if the Split(Char[]) method is passed a separator that is null or contains no characters, the method uses a slightly different set of white-space characters to split the string than the Trim(Char[]) method does to trim the string. Starting with .NET Framework 4, both methods use an identical set of Unicode white-space characters.

Applies to

Split(String[], StringSplitOptions)

Splits a string into substrings based on a specified delimiting string and, optionally, options.

public:
 cli::array <System::String ^> ^ Split(cli::array <System::String ^> ^ separator, StringSplitOptions options);
public string[] Split (string[] separator, StringSplitOptions options);
public string[] Split (string[]? separator, StringSplitOptions options);
[System.Runtime.InteropServices.ComVisible(false)]
public string[] Split (string[] separator, StringSplitOptions options);
member this.Split : string[] * StringSplitOptions -> string[]
[<System.Runtime.InteropServices.ComVisible(false)>]
member this.Split : string[] * StringSplitOptions -> string[]
Public Function Split (separator As String(), options As StringSplitOptions) As String()

Parameters

separator
String[]

An array of strings that delimit the substrings in this string, an empty array that contains no delimiters, or null.

options
StringSplitOptions

A bitwise combination of the enumeration values that specifies whether to trim substrings and include empty substrings.

Returns

String[]

An array whose elements contain the substrings in this string that are delimited by one or more strings in separator. For more information, see the Remarks section.

Attributes

Exceptions

options is not one of the StringSplitOptions values.

Examples

The following example illustrates the difference in the arrays returned by calling a string's String.Split(String[], StringSplitOptions) method with its options parameter equal to StringSplitOptions.None and StringSplitOptions.RemoveEmptyEntries.

string source = "[stop]ONE[stop][stop]TWO[stop][stop][stop]THREE[stop][stop]";
string[] stringSeparators = new string[] { "[stop]" };
string[] result;

// Display the original string and delimiter string.
Console.WriteLine($"Splitting the string:\n   \"{source}\".");
Console.WriteLine();
Console.WriteLine($"Using the delimiter string:\n   \"{stringSeparators[0]}\"");
Console.WriteLine();

// Split a string delimited by another string and return all elements.
result = source.Split(stringSeparators, StringSplitOptions.None);
Console.WriteLine($"Result including all elements ({result.Length} elements):");
Console.Write("   ");
foreach (string s in result)
{
    Console.Write("'{0}' ", String.IsNullOrEmpty(s) ? "<>" : s);
}
Console.WriteLine();
Console.WriteLine();

// Split delimited by another string and return all non-empty elements.
result = source.Split(stringSeparators, StringSplitOptions.RemoveEmptyEntries);
Console.WriteLine($"Result including non-empty elements ({result.Length} elements):");
Console.Write("   ");
foreach (string s in result)
{
    Console.Write("'{0}' ", String.IsNullOrEmpty(s) ? "<>" : s);
}
Console.WriteLine();

// The example displays the following output:
//    Splitting the string:
//       "[stop]ONE[stop][stop]TWO[stop][stop][stop]THREE[stop][stop]".
//    
//    Using the delimiter string:
//       "[stop]"
//    
//    Result including all elements (9 elements):
//       '<>' 'ONE' '<>' 'TWO' '<>' '<>' 'THREE' '<>' '<>'
//    
//    Result including non-empty elements (3 elements):
//       'ONE' 'TWO' 'THREE'
Dim source As String = "[stop]ONE[stop][stop]TWO[stop][stop][stop]THREE[stop][stop]"
Dim stringSeparators() As String = {"[stop]"}
Dim result() As String

' Display the original string and delimiter string.
Console.WriteLine("Splitting the string:{0}   '{1}'.", vbCrLf, source)
Console.WriteLine()
Console.WriteLine("Using the delimiter string:{0}   '{1}'.",
                vbCrLf, stringSeparators(0))
Console.WriteLine()

' Split a string delimited by another string and return all elements.
result = source.Split(stringSeparators, StringSplitOptions.None)
Console.WriteLine("Result including all elements ({0} elements):",
                result.Length)
Console.Write("   ")
For Each s As String In result
    Console.Write("'{0}' ", IIf(String.IsNullOrEmpty(s), "<>", s))
Next
Console.WriteLine()
Console.WriteLine()

' Split delimited by another string and return all non-empty elements.
result = source.Split(stringSeparators,
                    StringSplitOptions.RemoveEmptyEntries)
Console.WriteLine("Result including non-empty elements ({0} elements):",
                result.Length)
Console.Write("   ")
For Each s As String In result
    Console.Write("'{0}' ", IIf(String.IsNullOrEmpty(s), "<>", s))
Next
Console.WriteLine()

' The example displays the following output:
'    Splitting the string:
'       "[stop]ONE[stop][stop]TWO[stop][stop][stop]THREE[stop][stop]".
'    
'    Using the delimiter string:
'       "[stop]"
'    
'    Result including all elements (9 elements):
'       '<>' 'ONE' '<>' 'TWO' '<>' '<>' 'THREE' '<>' '<>'
'    
'    Result including non-empty elements (3 elements):
'       'ONE' 'TWO' 'THREE'

The following example defines an array of separators that include punctuation and white-space characters. Passing this array along with a value of StringSplitOptions.RemoveEmptyEntries to the Split(String[], StringSplitOptions) method returns an array that consists of the individual words from the string.

string[] separators = { ",", ".", "!", "?", ";", ":", " " };
string value = "The handsome, energetic, young dog was playing with his smaller, more lethargic litter mate.";
string[] words = value.Split(separators, StringSplitOptions.RemoveEmptyEntries);
foreach (var word in words)
    Console.WriteLine(word);

// The example displays the following output:
//       The
//       handsome
//       energetic
//       young
//       dog
//       was
//       playing
//       with
//       his
//       smaller
//       more
//       lethargic
//       litter
//       mate
    Dim separators() As String = {",", ".", "!", "?", ";", ":", " "}
    Dim value As String = "The handsome, energetic, young dog was playing with his smaller, more lethargic litter mate."
    Dim words() As String = value.Split(separators, StringSplitOptions.RemoveEmptyEntries)
    For Each word In words
        Console.WriteLine(word)
    Next
End Sub

' The example displays the following output:
'
'       The
'       handsome
'       energetic
'       young
'       dog
'       was
'       playing
'       with
'       his
'       smaller
'       more
'       lethargic
'       litter
'       mate

Note that the method is called with the options argument set to StringSplitOptions.RemoveEmptyEntries. This prevents the returned array from including String.Empty values that represent empty substring matches between punctuation marks and white-space characters.

Remarks

When a string is delimited by a known set of strings, you can use the Split method to separate it into substrings.

Delimiter strings are not included in the elements of the returned array. For example, if the separator array includes the string "--" and the value of the current string instance is "aa--bb--cc", the method returns an array that contains three elements: "aa", "bb", and "cc".

If this instance does not contain any of the strings in separator, the returned array consists of a single element that contains this instance.

If the options parameter is RemoveEmptyEntries and the length of this instance is zero, the method returns an empty array.

Each element of separator defines a separate delimiter that consists of one or more characters. If the options argument is None, and two delimiters are adjacent or a delimiter is found at the beginning or end of this instance, the corresponding array element contains String.Empty. For example, if separator includes two elements, "-" and "_", the value of the string instance is "-_aa-_", and the value of the options argument is None, the method returns a sting array with the following five elements:

  1. String.Empty, which represents the empty string that precedes the "-" substring at index 0.

  2. String.Empty, which represents the empty string between the "-" substring at index 0 and the "_" substring at index 1.

  3. "aa".

  4. String.Empty, which represents the empty string that follows the "-" substring at index 4.

  5. String.Empty, which represents the empty string that follows the "_" substring at index 5.

The separator array

If any of the elements in separator consists of multiple characters, the entire substring is considered a delimiter. For example, if one of the elements in separator is "10", attempting to split the string "This10is10a10string." returns the following four-element array: { "This", "is", "a", "string." }.

If the separator parameter is null or contains no non-empty strings, white-space characters are assumed to be the delimiters. White-space characters are defined by the Unicode standard and the Char.IsWhiteSpace method returns true if they are passed to it.

If the separator parameter in the call to this method overload is null, compiler overload resolution fails. To unambiguously identify the called method, your code must indicate the type of the null. The following example shows several ways to unambiguously identify this overload.

string phrase = "The quick  brown fox";

_ = phrase.Split(default(string[]), StringSplitOptions.RemoveEmptyEntries);

_ = phrase.Split((string[])null, StringSplitOptions.RemoveEmptyEntries);

_ = phrase.Split(null as string[], StringSplitOptions.RemoveEmptyEntries);
Dim phrase As String = "The quick brown fox"
Dim words() As String

words = phrase.Split(TryCast(Nothing, String()),
                       StringSplitOptions.RemoveEmptyEntries)

words = phrase.Split(New String() {},
                     StringSplitOptions.RemoveEmptyEntries)

Comparison details

The Split method extracts the substrings in this string that are delimited by one or more of the strings in the separator parameter, and returns those substrings as elements of an array.

The Split method looks for delimiters by performing comparisons using case-sensitive ordinal sort rules. For more information about word, string, and ordinal sorts, see the System.Globalization.CompareOptions enumeration.

The Split method ignores any element of separator whose value is null or the empty string ("").

To avoid ambiguous results when strings in separator have characters in common, the Split operation proceeds from the beginning to the end of the value of the instance, and matches the first element in separator that is equal to a delimiter in the instance. The order in which substrings are encountered in the instance takes precedence over the order of elements in separator.

For example, consider an instance whose value is "abcdef". If the first element in separator was "ef" and the second element was "bcde", the result of the split operation would be a string array that contains two elements, "a" and "f". This is because the substring in the instance, "bcde", is encountered and matches an element in separator before the substring "f" is encountered.

However, if the first element of separator was "bcd" and the second element was "bc", the result of the split operation would be a string array that contains two elements, "a" and "ef". This is because "bcd" is the first delimiter in separator that matches a delimiter in the instance. If the order of the separators was reversed so the first element was "bc" and the second element was "bcd", the result would be a string array that contains two elements, "a" and "def".

Performance considerations

The Split methods allocate memory for the returned array object and a String object for each array element. If your application requires optimal performance or if managing memory allocation is critical in your application, consider using the IndexOf or IndexOfAny method, and optionally the Compare method, to locate a substring within a string.

If you are splitting a string at a separator character, use the IndexOf or IndexOfAny method to locate a separator character in the string. If you are splitting a string at a separator string, use the IndexOf or IndexOfAny method to locate the first character of the separator string. Then use the Compare method to determine whether the characters after that first character are equal to the remaining characters of the separator string.

In addition, if the same set of characters is used to split strings in multiple Split method calls, consider creating a single array and referencing it in each method call. This significantly reduces the additional overhead of each method call.

Notes to Callers

In .NET Framework 3.5 and earlier versions, if the Split(Char[]) method is passed a separator that is null or contains no characters, the method uses a slightly different set of white-space characters to split the string than the Trim(Char[]) method does to trim the string. Starting with .NET Framework 4, both methods use an identical set of Unicode white-space characters.

Applies to

Split(String, Int32, StringSplitOptions)

Splits a string into a maximum number of substrings based on a specified delimiting string and, optionally, options.

public string[] Split (string? separator, int count, StringSplitOptions options = System.StringSplitOptions.None);
public string[] Split (string separator, int count, StringSplitOptions options = System.StringSplitOptions.None);
member this.Split : string * int * StringSplitOptions -> string[]
Public Function Split (separator As String, count As Integer, Optional options As StringSplitOptions = System.StringSplitOptions.None) As String()

Parameters

separator
String

A string that delimits the substrings in this instance.

count
Int32

The maximum number of elements expected in the array.

options
StringSplitOptions

A bitwise combination of the enumeration values that specifies whether to trim substrings and include empty substrings.

Returns

String[]

An array that contains at most count substrings from this instance that are delimited by separator.

Remarks

If the string has already been split count - 1 times, but the end of the string has not been reached, then the last string in the returned array will contain this instance's remaining trailing substring, untouched.

Applies to

Split(Char[], StringSplitOptions)

Splits a string into substrings based on specified delimiting characters and options.

public:
 cli::array <System::String ^> ^ Split(cli::array <char> ^ separator, StringSplitOptions options);
public string[] Split (char[] separator, StringSplitOptions options);
public string[] Split (char[]? separator, StringSplitOptions options);
[System.Runtime.InteropServices.ComVisible(false)]
public string[] Split (char[] separator, StringSplitOptions options);
member this.Split : char[] * StringSplitOptions -> string[]
[<System.Runtime.InteropServices.ComVisible(false)>]
member this.Split : char[] * StringSplitOptions -> string[]
Public Function Split (separator As Char(), options As StringSplitOptions) As String()

Parameters

separator
Char[]

An array of characters that delimit the substrings in this string, an empty array that contains no delimiters, or null.

options
StringSplitOptions

A bitwise combination of the enumeration values that specifies whether to trim substrings and include empty substrings.

Returns

String[]

An array whose elements contain the substrings in this string that are delimited by one or more characters in separator. For more information, see the Remarks section.

Attributes

Exceptions

options is not one of the StringSplitOptions values.

Examples

The following example uses the StringSplitOptions enumeration to include or exclude substrings generated by the Split method.

// This example demonstrates the String.Split(Char[], Boolean) and 
//                               String.Split(Char[], Int32, Boolean) methods
using namespace System;
void Show( array<String^>^entries )
{
   Console::WriteLine( "The return value contains these {0} elements:", entries->Length );
   System::Collections::IEnumerator^ myEnum = entries->GetEnumerator();
   while ( myEnum->MoveNext() )
   {
      String^ entry = safe_cast<String^>(myEnum->Current);
      Console::Write( "<{0}>", entry );
   }

   Console::Write( "{0}{0}", Environment::NewLine );
}

int main()
{
   String^ s = ",one,,,two,,,,,three,,";
   array<Char>^sep = gcnew array<Char>{
      ','
   };
   array<String^>^result;
   
   //
   Console::WriteLine( "The original string is \"{0}\".", s );
   Console::WriteLine( "The separation character is '{0}'.", sep[ 0 ] );
   Console::WriteLine();
   
   //
   Console::WriteLine( "Split the string and return all elements:" );
   result = s->Split( sep, StringSplitOptions::None );
   Show( result );
   
   //
   Console::WriteLine( "Split the string and return all non-empty elements:" );
   result = s->Split( sep, StringSplitOptions::RemoveEmptyEntries );
   Show( result );
   
   //
   Console::WriteLine( "Split the string and return 2 elements:" );
   result = s->Split( sep, 2, StringSplitOptions::None );
   Show( result );
   
   //
   Console::WriteLine( "Split the string and return 2 non-empty elements:" );
   result = s->Split( sep, 2, StringSplitOptions::RemoveEmptyEntries );
   Show( result );
}

/*
This example produces the following results:

The original string is ",one,,,two,,,,,three,,".
The separation character is ','.

Split the string and return all elements:
The return value contains these 12 elements:
<><one><><><two><><><><><three><><>

Split the string and return all non-empty elements:
The return value contains these 3 elements:
<one><two><three>

Split the string and return 2 elements:
The return value contains these 2 elements:
<><one,,,two,,,,,three,,>

Split the string and return 2 non-empty elements:
The return value contains these 2 elements:
<one><,,two,,,,,three,,>

*/
// This example demonstrates the String.Split() methods that use
// the StringSplitOptions enumeration.
string s1 = ",ONE,,TWO,,,THREE,,";
string s2 = "[stop]" +
            "ONE[stop][stop]" +
            "TWO[stop][stop][stop]" +
            "THREE[stop][stop]";
char[] charSeparators = new char[] { ',' };
string[] stringSeparators = new string[] { "[stop]" };
string[] result;
// ------------------------------------------------------------------------------
// Split a string delimited by characters.
// ------------------------------------------------------------------------------
Console.WriteLine("1) Split a string delimited by characters:\n");

// Display the original string and delimiter characters.
Console.WriteLine($"1a) The original string is \"{s1}\".");
Console.WriteLine($"The delimiter character is '{charSeparators[0]}'.\n");

// Split a string delimited by characters and return all elements.
Console.WriteLine("1b) Split a string delimited by characters and " +
                  "return all elements:");
result = s1.Split(charSeparators, StringSplitOptions.None);
Show(result);

// Split a string delimited by characters and return all non-empty elements.
Console.WriteLine("1c) Split a string delimited by characters and " +
                  "return all non-empty elements:");
result = s1.Split(charSeparators, StringSplitOptions.RemoveEmptyEntries);
Show(result);

// Split the original string into the string and empty string before the
// delimiter and the remainder of the original string after the delimiter.
Console.WriteLine("1d) Split a string delimited by characters and " +
                  "return 2 elements:");
result = s1.Split(charSeparators, 2, StringSplitOptions.None);
Show(result);

// Split the original string into the string after the delimiter and the
// remainder of the original string after the delimiter.
Console.WriteLine("1e) Split a string delimited by characters and " +
                  "return 2 non-empty elements:");
result = s1.Split(charSeparators, 2, StringSplitOptions.RemoveEmptyEntries);
Show(result);

// ------------------------------------------------------------------------------
// Split a string delimited by another string.
// ------------------------------------------------------------------------------
Console.WriteLine("2) Split a string delimited by another string:\n");

// Display the original string and delimiter string.
Console.WriteLine($"2a) The original string is \"{s2}\".");
Console.WriteLine($"The delimiter string is \"{stringSeparators[0]}\".\n");

// Split a string delimited by another string and return all elements.
Console.WriteLine("2b) Split a string delimited by another string and " +
                  "return all elements:");
result = s2.Split(stringSeparators, StringSplitOptions.None);
Show(result);

// Split the original string at the delimiter and return all non-empty elements.
Console.WriteLine("2c) Split a string delimited by another string and " +
                  "return all non-empty elements:");
result = s2.Split(stringSeparators, StringSplitOptions.RemoveEmptyEntries);
Show(result);

// Split the original string into the empty string before the
// delimiter and the remainder of the original string after the delimiter.
Console.WriteLine("2d) Split a string delimited by another string and " +
                  "return 2 elements:");
result = s2.Split(stringSeparators, 2, StringSplitOptions.None);
Show(result);

// Split the original string into the string after the delimiter and the
// remainder of the original string after the delimiter.
Console.WriteLine("2e) Split a string delimited by another string and " +
                  "return 2 non-empty elements:");
result = s2.Split(stringSeparators, 2, StringSplitOptions.RemoveEmptyEntries);
Show(result);

// Display the array of separated strings using a local function
void Show(string[] entries)
{
    Console.WriteLine($"The return value contains these {entries.Length} elements:");
    foreach (string entry in entries)
    {
        Console.Write($"<{entry}>");
    }
    Console.Write("\n\n");
}

/*
This example produces the following results:

1) Split a string delimited by characters:

1a) The original string is ",ONE,,TWO,,,THREE,,".
The delimiter character is ','.

1b) Split a string delimited by characters and return all elements:
The return value contains these 9 elements:
<><ONE><><TWO><><><THREE><><>

1c) Split a string delimited by characters and return all non-empty elements:
The return value contains these 3 elements:
<ONE><TWO><THREE>

1d) Split a string delimited by characters and return 2 elements:
The return value contains these 2 elements:
<><ONE,,TWO,,,THREE,,>

1e) Split a string delimited by characters and return 2 non-empty elements:
The return value contains these 2 elements:
<ONE><TWO,,,THREE,,>

2) Split a string delimited by another string:

2a) The original string is "[stop]ONE[stop][stop]TWO[stop][stop][stop]THREE[stop][stop]".
The delimiter string is "[stop]".

2b) Split a string delimited by another string and return all elements:
The return value contains these 9 elements:
<><ONE><><TWO><><><THREE><><>

2c) Split a string delimited by another string and return all non-empty elements:
The return value contains these 3 elements:
<ONE><TWO><THREE>

2d) Split a string delimited by another string and return 2 elements:
The return value contains these 2 elements:
<><ONE[stop][stop]TWO[stop][stop][stop]THREE[stop][stop]>

2e) Split a string delimited by another string and return 2 non-empty elements:
The return value contains these 2 elements:
<ONE><TWO[stop][stop][stop]THREE[stop][stop]>

*/
    Dim s1 As String = ",ONE,,TWO,,,THREE,,"
    Dim s2 As String = "[stop]" &
                       "ONE[stop][stop]" &
                       "TWO[stop][stop][stop]" &
                       "THREE[stop][stop]"
    Dim charSeparators() As Char = {","c}
    Dim stringSeparators() As String = {"[stop]"}
    Dim result() As String
    ' ------------------------------------------------------------------------------
    ' Split a string delimited by characters.
    ' ------------------------------------------------------------------------------
    Console.WriteLine("1) Split a string delimited by characters:" & vbCrLf)

    ' Display the original string and delimiter characters.
    Console.WriteLine("1a) The original string is ""{0}"".", s1)
    Console.WriteLine("The delimiter character is '{0}'." & vbCrLf, charSeparators(0))

    ' Split a string delimited by characters and return all elements.
    Console.WriteLine("1b) Split a string delimited by characters and " &
                      "return all elements:")
    result = s1.Split(charSeparators, StringSplitOptions.None)
    Show(result)

    ' Split a string delimited by characters and return all non-empty elements.
    Console.WriteLine("1c) Split a string delimited by characters and " &
                      "return all non-empty elements:")
    result = s1.Split(charSeparators, StringSplitOptions.RemoveEmptyEntries)
    Show(result)

    ' Split the original string into the string and empty string before the 
    ' delimiter and the remainder of the original string after the delimiter.
    Console.WriteLine("1d) Split a string delimited by characters and " &
                      "return 2 elements:")
    result = s1.Split(charSeparators, 2, StringSplitOptions.None)
    Show(result)

    ' Split the original string into the string after the delimiter and the 
    ' remainder of the original string after the delimiter.
    Console.WriteLine("1e) Split a string delimited by characters and " &
                      "return 2 non-empty elements:")
    result = s1.Split(charSeparators, 2, StringSplitOptions.RemoveEmptyEntries)
    Show(result)

    ' ------------------------------------------------------------------------------
    ' Split a string delimited by another string.
    ' ------------------------------------------------------------------------------
    Console.WriteLine("2) Split a string delimited by another string:" & vbCrLf)

    ' Display the original string and delimiter string.
    Console.WriteLine("2a) The original string is ""{0}"".", s2)
    Console.WriteLine("The delimiter string is ""{0}""." & vbCrLf, stringSeparators(0))

    ' Split a string delimited by another string and return all elements.
    Console.WriteLine("2b) Split a string delimited by another string and " &
                      "return all elements:")
    result = s2.Split(stringSeparators, StringSplitOptions.None)
    Show(result)

    ' Split the original string at the delimiter and return all non-empty elements.
    Console.WriteLine("2c) Split a string delimited by another string and " &
                      "return all non-empty elements:")
    result = s2.Split(stringSeparators, StringSplitOptions.RemoveEmptyEntries)
    Show(result)

    ' Split the original string into the empty string before the 
    ' delimiter and the remainder of the original string after the delimiter.
    Console.WriteLine("2d) Split a string delimited by another string and " &
                      "return 2 elements:")
    result = s2.Split(stringSeparators, 2, StringSplitOptions.None)
    Show(result)

    ' Split the original string into the string after the delimiter and the 
    ' remainder of the original string after the delimiter.
    Console.WriteLine("2e) Split a string delimited by another string and " &
                      "return 2 non-empty elements:")
    result = s2.Split(stringSeparators, 2, StringSplitOptions.RemoveEmptyEntries)
    Show(result)

End Sub


' Display the array of separated strings.
Public Shared Sub Show(ByVal entries() As String)
    Console.WriteLine("The return value contains these {0} elements:", entries.Length)
    Dim entry As String
    For Each entry In entries
        Console.Write("<{0}>", entry)
    Next entry
    Console.Write(vbCrLf & vbCrLf)

End Sub

'This example produces the following results:
'
'1) Split a string delimited by characters:
'
'1a) The original string is ",ONE,,TWO,,,THREE,,".
'The delimiter character is ','.
'
'1b) Split a string delimited by characters and return all elements:
'The return value contains these 9 elements:
'<><ONE><><TWO><><><THREE><><>
'
'1c) Split a string delimited by characters and return all non-empty elements:
'The return value contains these 3 elements:
'<ONE><TWO><THREE>
'
'1d) Split a string delimited by characters and return 2 elements:
'The return value contains these 2 elements:
'<><ONE,,TWO,,,THREE,,>
'
'1e) Split a string delimited by characters and return 2 non-empty elements:
'The return value contains these 2 elements:
'<ONE><TWO,,,THREE,,>
'
'2) Split a string delimited by another string:
'
'2a) The original string is "[stop]ONE[stop][stop]TWO[stop][stop][stop]THREE[stop][stop]".
'The delimiter string is "[stop]".
'
'2b) Split a string delimited by another string and return all elements:
'The return value contains these 9 elements:
'<><ONE><><TWO><><><THREE><><>
'
'2c) Split a string delimited by another string and return all non-empty elements:
'The return value contains these 3 elements:
'<ONE><TWO><THREE>
'
'2d) Split a string delimited by another string and return 2 elements:
'The return value contains these 2 elements:
'<><ONE[stop][stop]TWO[stop][stop][stop]THREE[stop][stop]>
'
'2e) Split a string delimited by another string and return 2 non-empty elements:
'The return value contains these 2 elements:
'<ONE><TWO[stop][stop][stop]THREE[stop][stop]>
'

Remarks

Delimiter characters (the characters in the separator array) are not included in the elements of the returned array. For example, if the separator array includes the character "-" and the value of the current string instance is "aa-bb-cc", the method returns an array that contains three elements: "aa", "bb", and "cc".

If this instance does not contain any of the characters in separator, the returned array consists of a single element that contains this instance.

If the options parameter is RemoveEmptyEntries and the length of this instance is zero, the method returns an empty array.

Each element of separator defines a separate delimiter that consists of a single character. If the options argument is None, and two delimiters are adjacent or a delimiter is found at the beginning or end of this instance, the corresponding array element contains String.Empty. For example, if separator includes two elements, "-" and "_", the value of the string instance is "-_aa-_", and the value of the options argument is None, the method returns a string array with the following five elements:

  1. String.Empty, which represents the empty string that precedes the "-" character at index 0.

  2. String.Empty, which represents the empty string between the "-" character at index 0 and the "_" character at index 1.

  3. "aa".

  4. String.Empty, which represents the empty string that follows the "-" character at index 4.

  5. String.Empty, which represents the empty string that follows the "_" character at index 5.

The separator array

If the separator parameter is null or contains no characters, white-space characters are assumed to be the delimiters. White-space characters are defined by the Unicode standard and the Char.IsWhiteSpace method returns true if they are passed to it.

If the separator parameter is null, compiler overload resolution fails. To unambiguously identify the called method, your code must indicate the type of the null. The following example shows several ways to unambiguously identify this overload.

string phrase = "The quick  brown fox";

_ = phrase.Split(default(char[]), StringSplitOptions.RemoveEmptyEntries);

_ = phrase.Split((char[])null, StringSplitOptions.RemoveEmptyEntries);

_ = phrase.Split(null as char[], StringSplitOptions.RemoveEmptyEntries);
Dim phrase As String = "The quick brown fox"
Dim words() As String

words = phrase.Split(TryCast(Nothing, Char()),
                       StringSplitOptions.RemoveEmptyEntries)

words = phrase.Split(New Char() {},
                     StringSplitOptions.RemoveEmptyEntries)

Comparison details

The Split method extracts the substrings in this string that are delimited by one or more of the characters in the separator parameter, and returns those substrings as elements of an array.

The Split method looks for delimiters by performing comparisons using case-sensitive ordinal sort rules. For more information about word, string, and ordinal sorts, see the System.Globalization.CompareOptions enumeration.

Performance considerations

The Split methods allocate memory for the returned array object and a String object for each array element. If your application requires optimal performance or if managing memory allocation is critical in your application, consider using the IndexOf or IndexOfAny method, and optionally the Compare method, to locate a substring within a string.

If you are splitting a string at a separator character, use the IndexOf or IndexOfAny method to locate a separator character in the string. If you are splitting a string at a separator string, use the IndexOf or IndexOfAny method to locate the first character of the separator string. Then use the Compare method to determine whether the characters after that first character are equal to the remaining characters of the separator string.

In addition, if the same set of characters is used to split strings in multiple Split method calls, consider creating a single array and referencing it in each method call. This significantly reduces the additional overhead of each method call.

Notes to Callers

In .NET Framework 3.5 and earlier versions, if the Split(Char[]) method is passed a separator that is null or contains no characters, the method uses a slightly different set of white-space characters to split the string than the Trim(Char[]) method does to trim the string. Starting with .NET Framework 4, both methods use an identical set of Unicode white-space characters.

Applies to

Split(Char[], Int32)

Splits a string into a maximum number of substrings based on specified delimiting characters.

public:
 cli::array <System::String ^> ^ Split(cli::array <char> ^ separator, int count);
public string[] Split (char[] separator, int count);
public string[] Split (char[]? separator, int count);
member this.Split : char[] * int -> string[]
Public Function Split (separator As Char(), count As Integer) As String()

Parameters

separator
Char[]

An array of characters that delimit the substrings in this string, an empty array that contains no delimiters, or null.

count
Int32

The maximum number of substrings to return.

Returns

String[]

An array whose elements contain the substrings in this instance that are delimited by one or more characters in separator. For more information, see the Remarks section.

Exceptions

count is negative.

Examples

The following example demonstrates how count can be used to limit the number of strings returned by Split.

string name = "Alex Johnson III";

string[] subs = name.Split(null, 2);

string firstName = subs[0];
string lastName;
if (subs.Length > 1)
{
    lastName = subs[1];
}

// firstName = "Alex"
// lastName = "Johnson III"
Console.WriteLine("What is your name?")
Dim name As String = Console.ReadLine()

Dim substrings = name.Split(Nothing, 2)
Dim firstName As String = substrings(0)
Dim lastName As String

If substrings.Length > 1 Then
    lastName = substrings(1)
End If

' If the user enters "Alex Johnson III":
' firstName = "Alex"
' lastName = "Johnson III"

Remarks

Delimiter characters are not included in the elements of the returned array.

If this instance does not contain any of the characters in separator, the returned array consists of a single element that contains this instance. If count is zero, an empty array is returned.

If the separator parameter is null or contains no characters, white-space characters are assumed to be the delimiters. White-space characters are defined by the Unicode standard and the Char.IsWhiteSpace method returns true if they are passed to it.

Each element of separator defines a separate delimiter character. If two delimiters are adjacent, or a delimiter is found at the beginning or end of this instance, the corresponding array element contains Empty.

If there are more than count substrings in this instance, the first count - 1 substrings are returned in the first count - 1 elements of the return value, and the remaining characters in this instance are returned in the last element of the return value.

If count is greater than the number of substrings, the available substrings are returned and no exception is thrown.

The following table shows some examples.

Language String value Separator Returned array
C# "42, 12, 19" new Char[] {',', ' '} {"42", "", "12", "", "19"}
Visual Basic "42, 12, 19" Char() = {","c, " "c}) {"42", "", "12", "", "19"}
C# "42..12..19." new Char[] {'.'} {"42", "", "12", "", "19", ""}
Visual Basic "42..12..19." Char() = {"."c} {"42", "", "12", "", "19", ""}
C# "Banana" new Char[] {'.'} {"Banana"}
Visual Basic "Banana" Char() = {"."c} {"Banana"}
C# "Darb\nSmarba" new Char[] {} {"Darb", "Smarba"}
Visual Basic "Darb" & vbLf & "Smarba" Char() = {} {"Darb", "Smarba"}
C# "Darb\nSmarba" null {"Darb", "Smarba"}
Visual Basic "Darb" & vbLf & "Smarba" Nothing {"Darb", "Smarba"}

Performance considerations

The Split methods allocate memory for the returned array object and a String object for each array element. If your application requires optimal performance or if managing memory allocation is critical in your application, consider using the IndexOf or IndexOfAny method, and optionally the Compare method, to locate a substring within a string.

If you are splitting a string at a separator character, use the IndexOf or IndexOfAny method to locate a separator character in the string. If you are splitting a string at a separator string, use the IndexOf or IndexOfAny method to locate the first character of the separator string. Then use the Compare method to determine whether the characters after that first character are equal to the remaining characters of the separator string.

In addition, if the same set of characters is used to split strings in multiple Split method calls, consider creating a single array and referencing it in each method call. This significantly reduces the additional overhead of each method call.

Notes to Callers

In .NET Framework 3.5 and earlier versions, if the Split(Char[]) method is passed a separator that is null or contains no characters, the method uses a slightly different set of white-space characters to split the string than the Trim(Char[]) method does to trim the string. Starting with .NET Framework 4, both methods use an identical set of Unicode white-space characters.

See also

Applies to

Split(Char, StringSplitOptions)

Splits a string into substrings based on a specified delimiting character and, optionally, options.

public string[] Split (char separator, StringSplitOptions options = System.StringSplitOptions.None);
member this.Split : char * StringSplitOptions -> string[]
Public Function Split (separator As Char, Optional options As StringSplitOptions = System.StringSplitOptions.None) As String()

Parameters

separator
Char

A character that delimits the substrings in this string.

options
StringSplitOptions

A bitwise combination of the enumeration values that specifies whether to trim substrings and include empty substrings.

Returns

String[]

An array whose elements contain the substrings from this instance that are delimited by separator.

Applies to

Split(String, StringSplitOptions)

Splits a string into substrings that are based on the provided string separator.

public string[] Split (string? separator, StringSplitOptions options = System.StringSplitOptions.None);
public string[] Split (string separator, StringSplitOptions options = System.StringSplitOptions.None);
member this.Split : string * StringSplitOptions -> string[]
Public Function Split (separator As String, Optional options As StringSplitOptions = System.StringSplitOptions.None) As String()

Parameters

separator
String

A string that delimits the substrings in this string.

options
StringSplitOptions

A bitwise combination of the enumeration values that specifies whether to trim substrings and include empty substrings.

Returns

String[]

An array whose elements contain the substrings from this instance that are delimited by separator.

Applies to

Split(Char[])

Splits a string into substrings based on specified delimiting characters.

public:
 cli::array <System::String ^> ^ Split(... cli::array <char> ^ separator);
public string[] Split (params char[] separator);
public string[] Split (params char[]? separator);
member this.Split : char[] -> string[]
Public Function Split (ParamArray separator As Char()) As String()

Parameters

separator
Char[]

An array of delimiting characters, an empty array that contains no delimiters, or null.

Returns

String[]

An array whose elements contain the substrings from this instance that are delimited by one or more characters in separator. For more information, see the Remarks section.

Examples

The following example demonstrates how to extract individual words from a block of text by treating the space character ( ) and tab character (\t) as delimiters. The string being split includes both of these characters.

string s = "Today\tI'm going to school";
string[] subs = s.Split(' ', '\t');

foreach (var sub in subs)
{
    Console.WriteLine($"Substring: {sub}");
}

// This example produces the following output:
//
// Substring: Today
// Substring: I'm
// Substring: going
// Substring: to
// Substring: school
Dim s As String = "Today" & vbTab & "I'm going to school"
Dim subs As String() = s.Split(" "c, Char.Parse(vbTab))

For Each substring In subs
    Console.WriteLine("Substring: " & substring)
Next

' This example produces the following output:
'
' Substring: Today
' Substring: I 'm
' Substring: going
' Substring: to
' Substring: school

Remarks

When a string is delimited by a known set of characters, you can use the Split(Char[]) method to separate it into substrings.

Delimiter characters are not included in the elements of the returned array. For example, if the separator array includes the character "-" and the value of the current string instance is "aa-bb-cc", the method returns an array that contains three elements: "aa", "bb", and "cc".

If this instance does not contain any of the characters in separator, the returned array consists of a single element that contains this instance.

Each element of separator defines a separate delimiter character. If two delimiters are adjacent, or a delimiter is found at the beginning or end of this instance, the corresponding element in the returned array contains Empty.

The following table shows some examples.

Language String value Separator Returned array
C# "42, 12, 19" new Char[] {',', ' '} {"42", "", "12", "", "19"}
Visual Basic "42, 12, 19" Char() = {","c, " "c}) {"42", "", "12", "", "19"}
C# "42..12..19." new Char[] {'.'} {"42", "", "12", "", "19", ""}
Visual Basic "42..12..19." Char() = {"."c} {"42", "", "12", "", "19", ""}
C# "Banana" new Char[] {'.'} {"Banana"}
Visual Basic "Banana" Char() = {"."c} {"Banana"}
C# "Darb\nSmarba" new Char[] {} {"Darb", "Smarba"}
Visual Basic "Darb" & vbLf & "Smarba" Char() = {} {"Darb", "Smarba"}
C# "Darb\nSmarba" null {"Darb", "Smarba"}
Visual Basic "Darb" & vbLf & "Smarba" Nothing {"Darb", "Smarba"}

The separator array

Each element of separator defines a separate delimiter that consists of a single character.

If the separator argument is null or contains no characters, the method treats white-space characters as the delimiters. White-space characters are defined by the Unicode standard, and the Char.IsWhiteSpace method returns true if a white-space character is passed to it.

String.Split(Char[]) and compiler overload resolution

Although the single parameter for this overload of String.Split is a character array, you can call it with a single character, as the following example shows.

string value = "This is a short string.";
char delimiter = 's';
string[] substrings = value.Split(delimiter);
foreach (var substring in substrings)
    Console.WriteLine(substring);

// The example displays the following output:
//     Thi
//      i
//      a
//     hort
//     tring.
    Dim value As String = "This is a short string."
    Dim delimiter As Char = "s"c
    Dim substrings() As String = value.Split(delimiter)
    For Each substring In substrings
        Console.WriteLine(substring)
    Next
End Sub

' The example displays the following output:
'
'     Thi
'      i
'      a
'     hort
'     tring.

Because the separator parameter is decorated with the ParamArrayAttribute attribute, compilers will interpret a single character as a single-element character array. This is not the case for other String.Split overloads that include a separator parameter; you must explicitly pass these overloads a character array as the separator argument.

Comparison details

The Split(Char[]) method extracts the substrings in this string that are delimited by one or more of the characters in the separator array, and returns those substrings as elements of an array.

The Split(Char[]) method looks for delimiters by performing comparisons using case-sensitive ordinal sort rules. For more information about word, string, and ordinal sorts, see the System.Globalization.CompareOptions enumeration.

Performance considerations

The Split methods allocate memory for the returned array object and a String object for each array element. If your application requires optimal performance or if managing memory allocation is critical in your application, consider using the IndexOf or IndexOfAny method. You also have the option of using the Compare method to locate a substring within a string.

To split a string at a separator character, use the IndexOf or IndexOfAny method to locate a separator character in the string. To split a string at a separator string, use the IndexOf or IndexOfAny method to locate the first character of the separator string. Then use the Compare method to determine whether the characters after that first character are equal to the remaining characters of the separator string.

In addition, if the same set of characters is used to split strings in multiple Split method calls, consider creating a single array and referencing it in each method call. This significantly reduces the additional overhead of each method call.

Notes to Callers

In .NET Framework 3.5 and earlier versions, if the Split(Char[]) method is passed a separator that is null or contains no characters, the method uses a slightly different set of white-space characters to split the string than the Trim(Char[]) method does to trim the string. Starting with .NET Framework 4, both methods use an identical set of Unicode white-space characters.

See also

Applies to