String.TrimStart String.TrimStart String.TrimStart String.TrimStart Method

定義

オーバーロード

TrimStart() TrimStart() TrimStart() TrimStart()
TrimStart(Char[]) TrimStart(Char[]) TrimStart(Char[]) TrimStart(Char[])

現在の String オブジェクトの先頭から、配列で指定された文字セットをすべて削除します。Removes all leading occurrences of a set of characters specified in an array from the current String object.

TrimStart(Char) TrimStart(Char) TrimStart(Char) TrimStart(Char)

TrimStart() TrimStart() TrimStart() TrimStart()

public:
 System::String ^ TrimStart();
public string TrimStart ();
member this.TrimStart : unit -> string
Public Function TrimStart () As String

戻り値

TrimStart(Char[]) TrimStart(Char[]) TrimStart(Char[]) TrimStart(Char[])

現在の String オブジェクトの先頭から、配列で指定された文字セットをすべて削除します。Removes all leading occurrences of a set of characters specified in an array from the current String object.

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

パラメーター

trimChars
Char[]

削除する Unicode 文字の配列、または nullAn array of Unicode characters to remove, or null.

戻り値

現在の文字列の先頭から、trimChars パラメーターの文字をすべて削除した後に残った文字列。The string that remains after all occurrences of characters in the trimChars parameter are removed from the start of the current string. trimCharsnull または空の配列の場合は、代わりに空白文字が削除されます。If trimChars is null or an empty array, white-space characters are removed instead.

次の例は、 TrimStartメソッドの基本的な機能を示しています。The following example demonstrates the basic functionality of the TrimStart method:

// TrimStart examples
string lineWithLeadingSpaces = "   Hello World!";
string lineWithLeadingSymbols = "$$$$Hello World!";
string lineWithLeadingUnderscores = "_____Hello World!";
string lineWithLeadingLetters = "xxxxHello World!";
string lineAfterTrimStart = string.Empty;

// Make it easy to print out and work with all of the examples
string[] lines = { lineWithLeadingSpaces, lineWithLeadingSymbols, lineWithLeadingUnderscores, lineWithLeadingLetters };

foreach (var line in lines)
{
    Console.WriteLine($"This line has leading characters: {line}");
}
// Output:
// This line has leading characters:    Hello World!
// This line has leading characters: $$$$Hello World!
// This line has leading characters: _____Hello World!
// This line has leading characters: xxxxHello World!

// A basic demonstration of TrimStart in action
lineAfterTrimStart = lineWithLeadingSpaces.TrimStart(' ');
Console.WriteLine($"This is the result after calling TrimStart: {lineAfterTrimStart}");
// This is the result after calling TrimStart: Hello World!   

// Since TrimStart accepts a character array of leading items to be removed as an argument,
// it's possible to do things like trim multiple pieces of data that each have different 
// leading characters,
foreach (var lineToEdit in lines)
{
    Console.WriteLine(lineToEdit.TrimStart(' ', '$', '_', 'x'));
}
// Result for each: Hello World!

// or handle pieces of data that have multiple kinds of leading characters 
var lineToBeTrimmed = "__###__ John Smith";
lineAfterTrimStart = lineToBeTrimmed.TrimStart('_', '#', ' ');
Console.WriteLine(lineAfterTrimStart);
// Result: John Smith
Public Sub Main()
   ' TrimStart Examples
   Dim lineWithLeadingSpaces as String = "   Hello World!"
   Dim lineWithLeadingSymbols as String = "$$$$Hello World!"
   Dim lineWithLeadingUnderscores as String = "_____Hello World!"
   Dim lineWithLeadingLetters as String = "xxxxHello World!"
   Dim lineAfterTrimStart = String.Empty

   ' Make it easy to print out and work with all of the examples
   Dim lines As String() = { lineWithLeadingSpaces, line lineWithLeadingSymbols, lineWithLeadingUnderscores, lineWithLeadingLetters }

   For Each line As String in lines
     Console.WriteLine($"This line has leading characters: {line}")
   Next
   ' Output:
   ' This line has leading characters:    Hello World!
   ' This line has leading characters: $$$$Hello World!
   ' This line has leading characters: _____Hello World!
   ' This line has leading characters: xxxxHello World!

   Console.WriteLine($"This line has leading spaces: {lineWithLeadingSpaces}")
   ' This line has leading spaces:   Hello World!

   ' A basic demonstration of TrimStart in action
   lineAfterTrimStart = lineWithLeadingSpaces.TrimStart(" "c)
   Console.WriteLine($"This is the result after calling TrimStart: {lineAfterTrimStart}")
   ' This is the result after calling TrimStart: Hello World!

   ' Since TrimStart accepts a character array of leading items to be removed as an argument,
   ' it's possible to do things like trim multiple pieces of data that each have different 
   ' leading characters,
   For Each lineToEdit As String in lines
     Console.WriteLine(lineToEdit.TrimStart(" "c, "$"c, "_"c, "x"c ))
   Next
   ' Result for each: Hello World!

   ' or handle pieces of data that have multiple kinds of leading characters
   Dim lineToBeTrimmed as String = "__###__ John Smith"
   lineAfterTrimStart = lineToBeTrimmed.TrimStart("_"c , "#"c , " "c)
   Console.WriteLine(lineAfterTrimStart)
   ' Result: John Smith

 End Sub

次の例ではTrimStart 、メソッドを使用して、ソースコードの行から空白とコメント文字を除去します。The following example uses the TrimStart method to trim white space and comment characters from lines of source code. メソッドStripCommentsは、のTrimStart呼び出しをラップし、空白とコメント文字を含む文字配列を渡します。これは、Visual Basic のアポストロフィ (') と、のC#スラッシュ (/) です。The StripComments method wraps a call to TrimStart and passes it a character array that contains a space and the comment character, which is an apostrophe ( ' ) in Visual Basic and a slash ( / ) in C#. 文字列TrimStartがコメントであるかどうかを評価するときに、先頭の空白を削除するメソッドも呼び出されます。The TrimStart method is also called to remove leading white space when evaluating whether a string is a comment.

public static string[] StripComments(string[] lines)
{
    List<string> lineList = new List<string>();
    foreach (string line in lines)
    {
        if (line.TrimStart(' ').StartsWith("//"))
            lineList.Add(line.TrimStart(' ', '/'));
    }
    return lineList.ToArray();
}
Public Shared Function StripComments(lines() As String) As String()
   Dim lineList As New List(Of String)
   For Each line As String In lines
      If line.TrimStart(" "c).StartsWith("'") Then
         linelist.Add(line.TrimStart("'"c, " "c))
      End If
   Next
   Return lineList.ToArray()
End Function   

StripComments メソッドを呼び出す例を次に示します。The following example then illustrates a call to the StripComments method.

public static void Main()
{
    string[] lines = {"using System;",
                   "",
                   "public class HelloWorld",
                   "{",
                   "   public static void Main()",
                   "   {",
                   "      // This code displays a simple greeting",
                   "      // to the console.",
                   "      Console.WriteLine(\"Hello, World.\");",
                   "   }",
                   "}"};
    Console.WriteLine("Before call to StripComments:");
    foreach (string line in lines)
        Console.WriteLine("   {0}", line);

    string[] strippedLines = StripComments(lines);
    Console.WriteLine("After call to StripComments:");
    foreach (string line in strippedLines)
        Console.WriteLine("   {0}", line);
}
// This code produces the following output to the console:
//    Before call to StripComments:
//       using System;
//   
//       public class HelloWorld
//       {
//           public static void Main()
//           {
//               // This code displays a simple greeting
//               // to the console.
//               Console.WriteLine("Hello, World.");
//           }
//       }  
//    After call to StripComments:
//       This code displays a simple greeting
//       to the console.
Public Shared Sub Main()
   Dim lines() As String = {"Public Module HelloWorld", _
                            "   Public Sub Main()", _
                            "      ' This code displays a simple greeting", _
                            "      ' to the console.", _
                            "      Console.WriteLine(""Hello, World."")", _
                            "   End Sub", _
                            " End Module"}
   Console.WriteLine("Code before call to StripComments:")
   For Each line As String In lines
      Console.WriteLine("   {0}", line)                         
   Next                            
   
   Dim strippedLines() As String = StripComments(lines) 
   Console.WriteLine("Code after call to StripComments:")
   For Each line As String In strippedLines
      Console.WriteLine("   {0}", line)                         
   Next                            
End Sub
' This code produces the following output to the console:
'    Code before call to StripComments:
'       Public Module HelloWorld
'          Public Sub Main()
'             ' This code displays a simple greeting
'             ' to the console.
'             Console.WriteLine("Hello, World.")
'          End Sub
'       End Module
'    Code after call to StripComments:
'       This code displays a simple greeting
'       to the console.   

注釈

メソッドTrimStartは、 trimCharsパラメーターに含まれるすべての先頭文字を現在の文字列から削除します。The TrimStart method removes from the current string all leading characters that are in the trimChars parameter. トリム操作は、に含まtrimCharsれていない文字が見つかったときに停止します。The trim operation stops when a character that is not in trimChars is encountered. たとえば、現在の文字列が "123abc456xyz789" trimCharsで、"1" ~ "9" の数字が含まれている場合、メソッドはTrimStart "abc456xyz789" を返します。For example, if the current string is "123abc456xyz789" and trimChars contains the digits from "1" through "9", the TrimStart method returns "abc456xyz789".

注意

メソッドがTrimStart現在のインスタンスから任意の文字を削除した場合、このメソッドは現在のインスタンスの値を変更しません。If the TrimStart method removes any characters from the current instance, this method does not modify the value of the current instance. 代わりに、現在のインスタンスで見つかったすべての先頭の空白文字が削除される新しい文字列を返します。Instead, it returns a new string in which all leading white space characters found in the current instance are removed.

注意 (呼び出し元)

以前.NET Framework 3.5 SP1.NET Framework 3.5 SP1のバージョンでは、がnullまたは空の配列の場合trimCharsに、このメソッドがトリムする空白文字の内部リストを保持します。The .NET Framework 3.5 SP1.NET Framework 3.5 SP1 and earlier versions maintains an internal list of white-space characters that this method trims if trimChars is null or an empty array. null trimChars IsWhiteSpace(Char)以降では、がまたは空の配列の場合、メソッドはすべての Unicode 空白文字 (つまり、メソッドに渡されるときtrueに戻り値を生成する文字) をトリムします。 .NET Framework 4.NET Framework 4Starting with the .NET Framework 4.NET Framework 4, if trimChars is null or an empty array, the method trims all Unicode white-space characters (that is, characters that produce a true return value when they are passed to the IsWhiteSpace(Char) method). この変更Trim()により、 .NET Framework 3.5 SP1.NET Framework 3.5 SP1およびそれより前のバージョンのメソッドでは、2つの文字、0の幅空間 (u + 200B)、およびゼロ幅の改行なしスペース ( Trim() u + FEFF .NET Framework 4.NET Framework 4 ) が削除されます。以降のバージョンのメソッドでは、削除しないでください。Because of this change, the Trim() method in the .NET Framework 3.5 SP1.NET Framework 3.5 SP1 and earlier versions removes two characters, ZERO WIDTH SPACE (U+200B) and ZERO WIDTH NO-BREAK SPACE (U+FEFF), that the Trim() method in the .NET Framework 4.NET Framework 4 and later versions does not remove. またTrim() 、以前のバージョンのメソッド.NET Framework 3.5 SP1.NET Framework 3.5 SP1では、3つの Unicode の空白文字は削除されません。モンゴル語の母音区切り記号 (U + 180 e)、ナロースペースなし (U + 202F)、および中程度の数学空間 (U + 205F)。In addition, the Trim() method in the .NET Framework 3.5 SP1.NET Framework 3.5 SP1 and earlier versions does not trim three Unicode white-space characters: MONGOLIAN VOWEL SEPARATOR (U+180E), NARROW NO-BREAK SPACE (U+202F), and MEDIUM MATHEMATICAL SPACE (U+205F).

こちらもご覧ください

TrimStart(Char) TrimStart(Char) TrimStart(Char) TrimStart(Char)

public:
 System::String ^ TrimStart(char trimChar);
public string TrimStart (char trimChar);
member this.TrimStart : char -> string
Public Function TrimStart (trimChar As Char) As String

パラメーター

trimChar
Char Char Char Char

戻り値

適用対象