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String.Split Method (Char[], Int32)

Returns a string array that contains the substrings in this instance that are delimited by elements of a specified Unicode character array. A parameter specifies the maximum number of substrings to return.

Namespace:  System
Assembly:  mscorlib (in mscorlib.dll)
public string[] Split(
	char[] separator,
	int count
)

Parameters

separator
Type: System.Char[]

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

count
Type: System.Int32

The maximum number of substrings to return.

Return Value

Type: System.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.
ExceptionCondition
ArgumentOutOfRangeException

count is negative.

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 return true if they are passed to the Char.IsWhiteSpace method.

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 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 following table provides examples.

String value

Separator

Count

Returned array

"42, 12, 19"

new Char[] {',', ' '} (C#)

Char() = {","c, " "c} (Visual Basic)

2

{"42", " 12, 19"}

"42..12..19"

new Char[] {'.'} (C#)

Char() = {"."c} (Visual Basic)

4

{"42", "", "12", ".19"}

"Banana"

new Char[] {'.'} (C#)

Char() = {"."c} (Visual Basic)

2

{"Banana"}

"Darb\nSmarba" (C#)

"Darb" & vbLf & "Smarba" (Visual Basic)

new Char[] {} (C#)

Char() = {} (Visual Basic)

1

{"Darb\nSmarba"} (C#)

"Darb" & vbLf & "Smarba" (Visual Basic)

"Darb\nSmarba" (C#)

"Darb" & vbLf & "Smarba" (Visual Basic)

new Char[] null (C#)

Char() = Nothing

2

{"Darb", "Smarba"}

"Darb\nSmarba" (C#)

"Darb" & vbLf & "Smarba" (Visual Basic)

new Char[] null (C#)

Char() = Nothing

100

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

The following example demonstrates how count affects the number of strings returned by Split.

using System;

public class StringSplit2 
{
   public static void Main() 
   {
      string delimStr = " ,.:";
	   char [] delimiter = delimStr.ToCharArray();
      string words = "one two,three:four.";
      string [] split = null;

	   Console.WriteLine("The delimiters are -{0}-", delimStr);
	   for (int x = 1; x <= 5; x++) 
      {
	      split = words.Split(delimiter, x);
         Console.WriteLine("\ncount = {0,2} ..............", x);
	       foreach (string s in split) 
          {
             Console.WriteLine("-{0}-", s);
  	       }
	   }
   }
}
// The example displays the following output: 
//       The delimiters are - ,.:- 
//       count =  1 .............. 
//       -one two,three:four.- 
//       count =  2 .............. 
//       -one- 
//       -two,three:four.- 
//       count =  3 .............. 
//       -one- 
//       -two- 
//       -three:four.- 
//       count =  4 .............. 
//       -one- 
//       -two- 
//       -three- 
//       -four.- 
//       count =  5 .............. 
//       -one- 
//       -two- 
//       -three- 
//       -four- 
//       --

.NET Framework

Supported in: 4.5.1, 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

.NET for Windows Store apps

Supported in: Windows 8

.NET for Windows Phone apps

Supported in: Windows Phone 8.1, Windows Phone 8, Silverlight 8.1

Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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