String.Join メソッド

public:
 static System::String ^ Join(char separator, ... cli::array <System::Object ^> ^ values);

public static string Join (char separator, params object[]? values);

public static string Join (char separator, params object[] values);

static member Join : char * obj[] -> string

Public Shared Function Join (separator As Char, ParamArray values As Object()) As String

パラメーター

戻り値

String

separator 文字で区切られた、values の要素で構成される文字列。A string that consists of the elements of values delimited by the separator character.

- または --or-

values に要素がない、または values のすべての要素が null の場合は Empty。Empty if values has zero elements or all the elements of values are null.

例外

public:
 static System::String ^ Join(char separator, ... cli::array <System::String ^> ^ value);

public static string Join (char separator, params string[]? value);

public static string Join (char separator, params string[] value);

static member Join : char * string[] -> string

Public Shared Function Join (separator As Char, ParamArray value As String()) As String

パラメーター

戻り値

String

separator 文字で区切られた、value の要素で構成される文字列。A string that consists of the elements of value delimited by the separator character.

- または --or-

value に要素がない、または value のすべての要素が null の場合は Empty。Empty if value has zero elements or all the elements of value are null.

例外

public:
 static System::String ^ Join(System::String ^ separator, System::Collections::Generic::IEnumerable<System::String ^> ^ values);

public static string Join (string separator, System.Collections.Generic.IEnumerable<string> values);

public static string Join (string? separator, System.Collections.Generic.IEnumerable<string>? values);

[System.Runtime.InteropServices.ComVisible(false)]
public static string Join (string separator, System.Collections.Generic.IEnumerable<string> values);

static member Join : string * seq<string> -> string

[<System.Runtime.InteropServices.ComVisible(false)>]
static member Join : string * seq<string> -> string

Public Shared Function Join (separator As String, values As IEnumerable(Of String)) As String

パラメーター

戻り値

String

values のメンバーからなる、separator 文字列で区切られた文字列。A string that consists of the members of values delimited by the separator string.

- または --or-

values に要素がない、または values のすべての要素が null の場合は Empty。Empty if values has zero elements or all the elements of values are null.

属性

ComVisibleAttribute

例外

例

次の例では、ありアルゴリズムのエラトステネスを使用して、100以下の素数を計算します。The following example uses the Sieve of Eratosthenes algorithm to calculate the prime numbers that are less than or equal to 100. 結果を List<T> 型のオブジェクトに代入し String 、次にメソッドに渡し Join(String, IEnumerable<String>) ます。It assigns the result to a List<T> object of type String, which it then passes to the Join(String, IEnumerable<String>) method.

using System;
using System.Collections.Generic;

public class Example
{
   public static void Main()
   {
      int maxPrime = 100;
      List<int> primes = GetPrimes(maxPrime);
      Console.WriteLine("Primes less than {0}:", maxPrime);
      Console.WriteLine("   {0}", String.Join(" ", primes));
   }

   private static List<int> GetPrimes(int maxPrime)
   {
      Array values = Array.CreateInstance(typeof(int), 
                              new int[] { maxPrime - 1}, new int[] { 2 });
      // Use Sieve of Eratosthenes to determine prime numbers.
      for (int ctr = values.GetLowerBound(0); ctr <= (int) Math.Ceiling(Math.Sqrt(values.GetUpperBound(0))); ctr++)
      {
                           
         if ((int) values.GetValue(ctr) == 1) continue;
         
         for (int multiplier = ctr; multiplier <=  maxPrime / 2; multiplier++)
            if (ctr * multiplier <= maxPrime)
               values.SetValue(1, ctr * multiplier);
      }      
      
      List<int> primes = new List<int>();
      for (int ctr = values.GetLowerBound(0); ctr <= values.GetUpperBound(0); ctr++)
         if ((int) values.GetValue(ctr) == 0) 
            primes.Add(ctr);
      return primes;
   }   
}
// The example displays the following output:
//    Primes less than 100:
//       2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89 97

Imports System.Collections.Generic

Module Example
   Public Sub Main()
      Dim maxPrime As Integer = 100
      Dim primes As List(Of String) = GetPrimes(maxPrime)
      Console.WriteLine("Primes less than {0}:", maxPrime)
      Console.WriteLine("   {0}", String.Join(" ", primes))
   End Sub
   
   Private Function GetPrimes(maxPrime As Integer) As List(Of String)
      Dim values As Array = Array.CreateInstance(GetType(Integer), _
                              New Integer() { maxPrime - 1}, New Integer(){ 2 }) 
        ' Use Sieve of Eratosthenes to determine prime numbers.
      For ctr As Integer = values.GetLowerBound(0) To _
                           CInt(Math.Ceiling(Math.Sqrt(values.GetUpperBound(0))))
         If CInt(values.GetValue(ctr)) = 1 Then Continue For
         
         For multiplier As Integer = ctr To maxPrime \ 2
            If ctr * multiplier <= maxPrime Then values.SetValue(1, ctr * multiplier)
         Next   
      Next      
      
      Dim primes As New List(Of String)
      For ctr As Integer = values.GetLowerBound(0) To values.GetUpperBound(0)
         If CInt(values.GetValue(ctr)) = 0 Then primes.Add(ctr.ToString())
      Next            
      Return primes
   End Function   
End Module
' The example displays the following output:
'    Primes less than 100:
'       2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89 97

注釈

がの場合は separator null 、代わりに空の文字列 ( String.Empty ) が使用されます。If separator is null, an empty string (String.Empty) is used instead. のいずれかのメンバーがの場合は values null 、空の文字列が代わりに使用されます。If any member of values is null, an empty string is used instead.

Join(String, IEnumerable<String>) は、 IEnumerable(Of String) 要素を最初に文字列配列に変換せずに、コレクション内の各要素を連結できる便利なメソッドです。Join(String, IEnumerable<String>) is a convenience method that lets you concatenate each element in an IEnumerable(Of String) collection without first converting the elements to a string array. これは、Language-Integrated クエリ (LINQ) クエリ式で特に便利です。It is particularly useful with Language-Integrated Query (LINQ) query expressions. 次の例では、 List(Of String) アルファベットの大文字または小文字を含むオブジェクトを、特定の文字以上の文字 (例では "M") を選択するラムダ式に渡します。The following example passes a List(Of String) object that contains either the uppercase or lowercase letters of the alphabet to a lambda expression that selects letters that are equal to or greater than a particular letter (which, in the example, is "M"). IEnumerable(Of String)メソッドによって返されるコレクション Enumerable.Where は、 Join(String, IEnumerable<String>) 結果を1つの文字列として表示するためにメソッドに渡されます。The IEnumerable(Of String) collection returned by the Enumerable.Where method is passed to the Join(String, IEnumerable<String>) method to display the result as a single string.

using System;
using System.Collections.Generic;
using System.Linq;

public class Example
{
   public static void Main()
   {
      string output = String.Join(" ", GetAlphabet(true).Where( letter => 
                      letter.CompareTo("M") >= 0));
      Console.WriteLine(output);  
   }

   private static List<string> GetAlphabet(bool upper)
   {
      List<string> alphabet = new List<string>();
      int charValue = upper ? 65 : 97;
      for (int ctr = 0; ctr <= 25; ctr++)
         alphabet.Add(Convert.ToChar(charValue + ctr).ToString());
      return alphabet; 
   }
}
// The example displays the following output:
//      M N O P Q R S T U V W X Y Z

Imports System.Collections.Generic
Imports System.Linq

Module modMain
   Public Sub Main()
      Dim output As String = String.Join(" ", GetAlphabet(True).Where(Function(letter) _
                                                         letter >= "M"))
        
      Console.WriteLine(output)                                     
   End Sub
   
   Private Function GetAlphabet(upper As Boolean) As List(Of String)
      Dim alphabet As New List(Of String)
      Dim charValue As Integer = CInt(IIf(upper, 65, 97))
      For ctr As Integer = 0 To 25
         alphabet.Add(ChrW(charValue + ctr).ToString())
      Next
      Return alphabet 
   End Function
End Module
' The example displays the following output:
'      M N O P Q R S T U V W X Y Z

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• Split(Char[])

public:
 static System::String ^ Join(System::String ^ separator, ... cli::array <System::Object ^> ^ values);

public static string Join (string separator, params object[] values);

public static string Join (string? separator, params object[]? values);

[System.Runtime.InteropServices.ComVisible(false)]
public static string Join (string separator, params object[] values);

static member Join : string * obj[] -> string

[<System.Runtime.InteropServices.ComVisible(false)>]
static member Join : string * obj[] -> string

Public Shared Function Join (separator As String, ParamArray values As Object()) As String

パラメーター

戻り値

String

values の要素からなる、separator 文字列で区切られた文字列。A string that consists of the elements of values delimited by the separator string. values が空の配列の場合、メソッドは Empty を返します。If values is an empty array, the method returns Empty.

属性

ComVisibleAttribute

例外

例

次の例では、ありアルゴリズムのエラトステネスを使用して、100以下の素数を計算します。The following example uses the Sieve of Eratosthenes algorithm to calculate the prime numbers that are less than or equal to 100. 結果を整数の配列に代入し、次にメソッドに渡し Join(String, Object[]) ます。It assigns the result to a integer array, which it then passes to the Join(String, Object[]) method.

using System;
using System.Collections.Generic;

public class Example
{
   public static void Main()
   {
      int maxPrime = 100;
      int[] primes = GetPrimes(maxPrime);
      Console.WriteLine("Primes less than {0}:", maxPrime);
      Console.WriteLine("   {0}", String.Join(" ", primes));
   }

   private static int[] GetPrimes(int maxPrime)
   {
      Array values = Array.CreateInstance(typeof(int), 
                              new int[] { maxPrime - 1}, new int[] { 2 }); 
      // Use Sieve of Eratosthenes to determine prime numbers.
      for (int ctr = values.GetLowerBound(0); ctr <= (int) Math.Ceiling(Math.Sqrt(values.GetUpperBound(0))); ctr++)
      {
                           
         if ((int) values.GetValue(ctr) == 1) continue;
         
         for (int multiplier = ctr; multiplier <=  maxPrime / 2; multiplier++)
            if (ctr * multiplier <= maxPrime)
               values.SetValue(1, ctr * multiplier);
      }      
      
      List<int> primes = new List<int>();
      for (int ctr = values.GetLowerBound(0); ctr <= values.GetUpperBound(0); ctr++)
         if ((int) values.GetValue(ctr) == 0) 
            primes.Add(ctr);
      return primes.ToArray();
   }   
}
// The example displays the following output:
//    Primes less than 100:
//       2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89 97

Module Example
   Public Sub Main()
      Dim maxPrime As Integer = 100
      Dim primes() As Integer = GetPrimes(maxPrime)
      Console.WriteLine("Primes less than {0}:", maxPrime)
      Console.WriteLine("   {0}", String.Join(" ", primes))
   End Sub
   
   Private Function GetPrimes(maxPrime As Integer) As Integer()
      Dim values As Array = Array.CreateInstance(GetType(Integer), _
                              New Integer() { maxPrime - 1}, New Integer(){ 2 }) 
        ' Use Sieve of Eratosthenes to determine prime numbers.
      For ctr As Integer = values.GetLowerBound(0) To _
                           CInt(Math.Ceiling(Math.Sqrt(values.GetUpperBound(0))))
         If CInt(values.GetValue(ctr)) = 1 Then Continue For
         
         For multiplier As Integer = ctr To maxPrime \ 2
            If ctr * multiplier <= maxPrime Then values.SetValue(1, ctr * multiplier)
         Next   
      Next      
      
      Dim primes As New System.Collections.Generic.List(Of Integer)
      For ctr As Integer = values.GetLowerBound(0) To values.GetUpperBound(0)
         If CInt(values.GetValue(ctr)) = 0 Then primes.Add(ctr)
      Next            
      Return primes.ToArray()
   End Function   
End Module
' The example displays the following output:
'    Primes less than 100:
'       2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89 97

注釈

がの場合、 separator null または最初の要素以外のの要素がの場合は values null 、代わりに空の文字列 ( String.Empty ) が使用されます。If separator is null or if any element of values other than the first element is null, an empty string (String.Empty) is used instead. の最初の要素がの場合は、「呼び出し元のメモ」セクションを参照してください values null 。See the Notes for Callers section if the first element of values is null.

Join(String, Object[]) は、要素を文字列に明示的に変換せずに、オブジェクト配列内の各要素を連結できる便利なメソッドです。Join(String, Object[]) is a convenience method that lets you concatenate each element in an object array without explicitly converting its elements to strings. 配列内の各オブジェクトの文字列形式は、そのオブジェクトのメソッドを呼び出すことによって派生され ToString ます。The string representation of each object in the array is derived by calling that object's ToString method.

注意 (呼び出し元)

の最初の要素がの場合、メソッドはの values null Join(String, Object[]) 要素を連結せずに、 values を返し Empty ます。If the first element of values is null, the Join(String, Object[]) method does not concatenate the elements in values but instead returns Empty. この問題の回避策は多数あります。A number of workarounds for this issue are available. 最も簡単な方法は、次の Empty 例に示すように、配列の最初の要素に値を代入することです。The easiest is to assign a value of Empty to the first element of the array, as the following example shows.

[! code-csharp-interactive# 6][! code-vbsystem.string. Join # 6][!code-csharp-interactiveSystem.String.Join#6] [!code-vbSystem.String.Join#6]

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• Split(Char[])

public:
 static System::String ^ Join(System::String ^ separator, ... cli::array <System::String ^> ^ value);

public:
 static System::String ^ Join(System::String ^ separator, cli::array <System::String ^> ^ value);

public static string Join (string separator, params string[] value);

public static string Join (string? separator, params string[]? value);

public static string Join (string separator, string[] value);

static member Join : string * string[] -> string

Public Shared Function Join (separator As String, ParamArray value As String()) As String

Public Shared Function Join (separator As String, value As String()) As String

パラメーター

戻り値

String

value 内の要素からなる、separator 文字列で区切られた文字列。A string that consists of the elements in value delimited by the separator string. value が空の配列の場合、メソッドは Empty を返します。If value is an empty array, the method returns Empty.

例外

例

Joinメソッドの例を次に示します。The following example demonstrates the Join method.

using namespace System;
String^ MakeLine( int initVal, int multVal, String^ sep )
{
   array<String^>^sArr = gcnew array<String^>(10);
   for ( int i = initVal; i < initVal + 10; i++ )
      sArr[ i - initVal ] = String::Format( "{0, -3}", i * multVal );
   return String::Join( sep, sArr );
}

int main()
{
   Console::WriteLine( MakeLine( 0, 5, ", " ) );
   Console::WriteLine( MakeLine( 1, 6, "  " ) );
   Console::WriteLine( MakeLine( 9, 9, ": " ) );
   Console::WriteLine( MakeLine( 4, 7, "< " ) );
}
// The example displays the following output:
//       0  , 5  , 10 , 15 , 20 , 25 , 30 , 35 , 40 , 45
//       6    12   18   24   30   36   42   48   54   60
//       81 : 90 : 99 : 108: 117: 126: 135: 144: 153: 162
//       28 < 35 < 42 < 49 < 56 < 63 < 70 < 77 < 84 < 91

using System;

public class JoinTest
{
    public static void Main()
    {
        Console.WriteLine(MakeLine(0, 5, ", "));
        Console.WriteLine(MakeLine(1, 6, "  "));
        Console.WriteLine(MakeLine(9, 9, ": "));
        Console.WriteLine(MakeLine(4, 7, "< "));
    }

    private static string MakeLine(int initVal, int multVal, string sep)
    {
        string [] sArr = new string [10];

        for (int i = initVal; i < initVal + 10; i++)
            sArr[i - initVal] = String.Format("{0,-3}", i * multVal);

        return String.Join(sep, sArr);
    }
}
// The example displays the following output:
//       0  , 5  , 10 , 15 , 20 , 25 , 30 , 35 , 40 , 45
//       6    12   18   24   30   36   42   48   54   60
//       81 : 90 : 99 : 108: 117: 126: 135: 144: 153: 162
//       28 < 35 < 42 < 49 < 56 < 63 < 70 < 77 < 84 < 91

Public Class JoinTest
    
    Public Shared Sub Main()
        
        Console.WriteLine(MakeLine(0, 5, ", "))
        Console.WriteLine(MakeLine(1, 6, "  "))
        Console.WriteLine(MakeLine(9, 9, ": "))
        Console.WriteLine(MakeLine(4, 7, "< "))
    End Sub
    
    
    Private Shared Function MakeLine(initVal As Integer, multVal As Integer, sep As String) As String
        Dim sArr(10) As String
        Dim i As Integer
        
        
        For i = initVal To (initVal + 10) - 1
            sArr((i - initVal)) = [String].Format("{0,-3}", i * multVal)
        
        Next i
        Return [String].Join(sep, sArr)
    End Function 'MakeLine
End Class
' The example displays the following output:
'       0  , 5  , 10 , 15 , 20 , 25 , 30 , 35 , 40 , 45
'       6    12   18   24   30   36   42   48   54   60
'       81 : 90 : 99 : 108: 117: 126: 135: 144: 153: 162
'       28 < 35 < 42 < 49 < 56 < 63 < 70 < 77 < 84 < 91

注釈

たとえば、 separator が "," で、の要素が value "apple"、"オレンジ"、"grape"、および "pear" の場合、は Join(separator, value) "apple, オレンジ, grape, pear" を返します。For example, if separator is ", " and the elements of value are "apple", "orange", "grape", and "pear", Join(separator, value) returns "apple, orange, grape, pear".

がの場合は separator null 、代わりに空の文字列 ( String.Empty ) が使用されます。If separator is null, an empty string (String.Empty) is used instead. 内のいずれかの要素がの場合は value null 、代わりに空の文字列が使用されます。If any element in value is null, an empty string is used instead.

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• Concat(Object)

public:
 static System::String ^ Join(char separator, cli::array <System::String ^> ^ value, int startIndex, int count);

public static string Join (char separator, string[]? value, int startIndex, int count);

public static string Join (char separator, string[] value, int startIndex, int count);

static member Join : char * string[] * int * int -> string

Public Shared Function Join (separator As Char, value As String(), startIndex As Integer, count As Integer) As String

パラメーター

戻り値

String

separator 文字で区切られた、value の要素で構成される文字列。A string that consists of the elements of value delimited by the separator character.

- または --or-

count が 0 である場合、value に要素がない場合、または value のすべての要素が null または Empty である場合は Empty。Empty if count is zero, value has no elements, or all the elements of value are null or Empty.

例外

public:
 static System::String ^ Join(System::String ^ separator, cli::array <System::String ^> ^ value, int startIndex, int count);

public static string Join (string separator, string[] value, int startIndex, int count);

public static string Join (string? separator, string[]? value, int startIndex, int count);

static member Join : string * string[] * int * int -> string

Public Shared Function Join (separator As String, value As String(), startIndex As Integer, count As Integer) As String

パラメーター

戻り値

String

value 内の文字列からなる、separator 文字列で区切られた文字列。A string that consists of the strings in value delimited by the separator string.

- または --or-

Empty が 0 である場合、または count に要素がない場合、または value と separator のすべての要素が value である場合、Empty。Empty if count is zero, value has no elements, or separator and all the elements of value are Empty.

例外

例

次の例では、果物という名前の配列の2つの要素を連結しています。The following example concatenates two elements from an array of names of fruit.

// Sample for String::Join(String, String[], int int)
using namespace System;
int main()
{
   array<String^>^val = {"apple","orange","grape","pear"};
   String^ sep = ", ";
   String^ result;
   Console::WriteLine( "sep = '{0}'", sep );
   Console::WriteLine( "val[] = {{'{0}' '{1}' '{2}' '{3}'}}", val[ 0 ], val[ 1 ], val[ 2 ], val[ 3 ] );
   result = String::Join( sep, val, 1, 2 );
   Console::WriteLine( "String::Join(sep, val, 1, 2) = '{0}'", result );
}

/*
This example produces the following results:
sep = ', '
val[] = {'apple' 'orange' 'grape' 'pear'}
String::Join(sep, val, 1, 2) = 'orange, grape'
*/

String[] val = {"apple", "orange", "grape", "pear"};
String sep   = ", ";
String result;

Console.WriteLine("sep = '{0}'", sep);
Console.WriteLine("val[] = {{'{0}' '{1}' '{2}' '{3}'}}", val[0], val[1], val[2], val[3]);
result = String.Join(sep, val, 1, 2);
Console.WriteLine("String.Join(sep, val, 1, 2) = '{0}'", result);

// This example produces the following results:
// sep = ', '
// val[] = {'apple' 'orange' 'grape' 'pear'}
// String.Join(sep, val, 1, 2) = 'orange, grape'

Class Sample
   Public Shared Sub Main()
      Dim val As [String]() =  {"apple", "orange", "grape", "pear"}
      Dim sep As [String] = ", "
      Dim result As [String]
      
      Console.WriteLine("sep = '{0}'", sep)
      Console.WriteLine("val() = {{'{0}' '{1}' '{2}' '{3}'}}", val(0), val(1), val(2), val(3))
      result = [String].Join(sep, val, 1, 2)
      Console.WriteLine("String.Join(sep, val, 1, 2) = '{0}'", result)
   End Sub
End Class 
'This example displays the following output:
'       sep = ', '
'       val() = {'apple' 'orange' 'grape' 'pear'}
'       String.Join(sep, val, 1, 2) = 'orange, grape'

注釈

たとえば、 separator が "," で、の要素が value "apple"、"オレンジ"、"grape"、および "pear" の場合、は Join(separator, value, 1, 2) "オレンジ, grape" を返します。For example, if separator is ", " and the elements of value are "apple", "orange", "grape", and "pear", Join(separator, value, 1, 2) returns "orange, grape".

がの場合は separator null 、代わりに空の文字列 ( String.Empty ) が使用されます。If separator is null, an empty string (String.Empty) is used instead. 内のいずれかの要素がの場合は value null 、代わりに空の文字列が使用されます。If any element in value is null, an empty string is used instead.

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• Split(Char[])

public:
generic <typename T>
 static System::String ^ Join(char separator, System::Collections::Generic::IEnumerable<T> ^ values);

public static string Join<T> (char separator, System.Collections.Generic.IEnumerable<T> values);

static member Join : char * seq<'T> -> string

Public Shared Function Join(Of T) (separator As Char, values As IEnumerable(Of T)) As String

型パラメーター

パラメーター

戻り値

String

separator 文字で区切られた values のメンバーで構成される文字列。A string that consists of the members of values delimited by the separator character. values にメンバーがない場合、メソッドは Empty を返します。If values has no members, the method returns Empty.

例外

public:
generic <typename T>
 static System::String ^ Join(System::String ^ separator, System::Collections::Generic::IEnumerable<T> ^ values);

public static string Join<T> (string separator, System.Collections.Generic.IEnumerable<T> values);

public static string Join<T> (string? separator, System.Collections.Generic.IEnumerable<T> values);

[System.Runtime.InteropServices.ComVisible(false)]
public static string Join<T> (string separator, System.Collections.Generic.IEnumerable<T> values);

static member Join : string * seq<'T> -> string

[<System.Runtime.InteropServices.ComVisible(false)>]
static member Join : string * seq<'T> -> string

Public Shared Function Join(Of T) (separator As String, values As IEnumerable(Of T)) As String

型パラメーター

パラメーター

戻り値

String

values のメンバーからなる、separator 文字列で区切られた文字列。A string that consists of the members of values delimited by the separator string. values にメンバーがない場合、メソッドは Empty を返します。If values has no members, the method returns Empty.

属性

ComVisibleAttribute

例外

例

次の例では、ありアルゴリズムのエラトステネスを使用して、100以下の素数を計算します。The following example uses the Sieve of Eratosthenes algorithm to calculate the prime numbers that are less than or equal to 100. 結果を List<T> integer 型のオブジェクトに代入し、次にメソッドに渡し Join<T>(String, IEnumerable<T>) ます。It assigns the result to a List<T> object of type integer, which it then passes to the Join<T>(String, IEnumerable<T>) method.

using System;
using System.Collections.Generic;

public class Example
{
   public static void Main()
   {
      int maxPrime = 100;
      List<int> primes = GetPrimes(maxPrime);
      Console.WriteLine("Primes less than {0}:", maxPrime);
      Console.WriteLine("   {0}", String.Join(" ", primes));
   }

   private static List<int> GetPrimes(int maxPrime)
   {
      Array values = Array.CreateInstance(typeof(int), 
                              new int[] { maxPrime - 1}, new int[] { 2 });
      // Use Sieve of Eratosthenes to determine prime numbers.
      for (int ctr = values.GetLowerBound(0); ctr <= (int) Math.Ceiling(Math.Sqrt(values.GetUpperBound(0))); ctr++)
      {
                           
         if ((int) values.GetValue(ctr) == 1) continue;
         
         for (int multiplier = ctr; multiplier <=  maxPrime / 2; multiplier++)
            if (ctr * multiplier <= maxPrime)
               values.SetValue(1, ctr * multiplier);
      }      
      
      List<int> primes = new List<int>();
      for (int ctr = values.GetLowerBound(0); ctr <= values.GetUpperBound(0); ctr++)
         if ((int) values.GetValue(ctr) == 0) 
            primes.Add(ctr);
      return primes;
   }   
}
// The example displays the following output:
//    Primes less than 100:
//       2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89 97

Imports System.Collections.Generic

Module Example
   Public Sub Main()
      Dim maxPrime As Integer = 100
      Dim primes As List(Of Integer) = GetPrimes(maxPrime)
      Console.WriteLine("Primes less than {0}:", maxPrime)
      Console.WriteLine("   {0}", String.Join(" ", primes))
   End Sub
   
   Private Function GetPrimes(maxPrime As Integer) As List(Of Integer)
      Dim values As Array = Array.CreateInstance(GetType(Integer), _
                              New Integer() { maxPrime - 1}, New Integer(){ 2 }) 
        ' Use Sieve of Eratosthenes to determine prime numbers.
      For ctr As Integer = values.GetLowerBound(0) To _
                           CInt(Math.Ceiling(Math.Sqrt(values.GetUpperBound(0))))
         If CInt(values.GetValue(ctr)) = 1 Then Continue For
         
         For multiplier As Integer = ctr To maxPrime \ 2
            If ctr * multiplier <= maxPrime Then values.SetValue(1, ctr * multiplier)
         Next   
      Next      
      
      Dim primes As New System.Collections.Generic.List(Of Integer)
      For ctr As Integer = values.GetLowerBound(0) To values.GetUpperBound(0)
         If CInt(values.GetValue(ctr)) = 0 Then primes.Add(ctr)
      Next            
      Return primes
   End Function   
End Module
' The example displays the following output:
'    Primes less than 100:
'       2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89 97

注釈

がの場合は separator null 、代わりに空の文字列 ( String.Empty ) が使用されます。If separator is null, an empty string (String.Empty) is used instead. のいずれかのメンバーがの場合は values null 、空の文字列が代わりに使用されます。If any member of values is null, an empty string is used instead.

Join<T>(String, IEnumerable<T>) は、最初にコレクションの各メンバーを IEnumerable<T> 文字列に変換せずに連結できる便利なメソッドです。Join<T>(String, IEnumerable<T>) is a convenience method that lets you concatenate each member of an IEnumerable<T> collection without first converting them to strings. コレクション内の各オブジェクトの文字列形式 IEnumerable<T> は、そのオブジェクトのメソッドを呼び出すことによって派生され ToString ます。The string representation of each object in the IEnumerable<T> collection is derived by calling that object's ToString method.

このメソッドは、Language-Integrated クエリ (LINQ) クエリ式で特に便利です。This method is particular useful with Language-Integrated Query (LINQ) query expressions. たとえば、次のコードでは、 Animal 動物の名前とそれが属する順序を含む非常に単純なクラスを定義しています。For example, the following code defines a very simple Animal class that contains the name of an animal and the order to which it belongs. 次に、 List<T> 多数のオブジェクトを含むオブジェクトを定義し Animal ます。It then defines a List<T> object that contains a number of Animal objects. Enumerable.Where拡張メソッドは、 Animal プロパティが "げっ歯類" と等しいオブジェクトを抽出するために呼び出され Order ます。The Enumerable.Where extension method is called to extract the Animal objects whose Order property equals "Rodent". 結果はメソッドに渡され Join<T>(String, IEnumerable<T>) ます。The result is passed to the Join<T>(String, IEnumerable<T>) method.

using System;
using System.Collections.Generic;
using System.Linq;

public class Animal
{
   public string Kind;
   public string Order;
   
   public Animal(string kind, string order)
   {
      this.Kind = kind;
      this.Order = order;
   }
   
   public override string ToString()
   {
      return this.Kind;
   }
}

public class Example
{
   public static void Main()
   {
      List<Animal> animals = new List<Animal>();
      animals.Add(new Animal("Squirrel", "Rodent"));
      animals.Add(new Animal("Gray Wolf", "Carnivora"));
      animals.Add(new Animal("Capybara", "Rodent"));
      string output = String.Join(" ", animals.Where( animal => 
                      (animal.Order == "Rodent")));
      Console.WriteLine(output);  
   }
}
// The example displays the following output:
//      Squirrel Capybara

Imports System.Collections.Generic

Public Class Animal
   Public Kind As String
   Public Order As String
   
   Public Sub New(kind As String, order As String)
      Me.Kind = kind
      Me.Order = order
   End Sub
   
   Public Overrides Function ToString() As String
      Return Me.Kind
   End Function
End Class

Module Example
   Public Sub Main()
      Dim animals As New List(Of Animal)
      animals.Add(New Animal("Squirrel", "Rodent"))
      animals.Add(New Animal("Gray Wolf", "Carnivora"))
      animals.Add(New Animal("Capybara", "Rodent")) 
      Dim output As String = String.Join(" ", animals.Where(Function(animal) _
                                           animal.Order = "Rodent"))
      Console.WriteLine(output)                                           
   End Sub
End Module
' The example displays the following output:
'      Squirrel Capybara

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