String.Split Method (Char[]) (System)

.NET Framework Class Library

String..::.Split Method (array<Char>[]()[])

Updated: May 2009

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

Namespace: System
Assembly: mscorlib (in mscorlib.dll)

Syntax

Visual Basic (Declaration)

Public Function Split ( _
    ParamArray separator As Char() _
) As String()

Visual Basic (Usage)

Dim instance As String
Dim separator As Char()
Dim returnValue As String()

returnValue = instance.Split(separator)

public string[] Split(
    params char[] separator
)

Visual C++

public:
array<String^>^ Split(
    ... array<wchar_t>^ separator
)

JScript

public function Split(
    ... separator : char[]
) : String[]

Parameters

separator: Type: array<System..::.Char>[]()[]
An array of Unicode characters that delimit the substrings in this instance, an empty array that contains no delimiters, or nullNothingnullptra null reference (Nothing in Visual Basic).

Return Value

Type: array<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.

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 the separator parameter is nullNothingnullptra null reference (Nothing in Visual Basic) or contains no characters, white-space characters are assumed to be the delimiters. The following table lists the white-space characters recognized by the Split method. (It is slightly different than the white-space characters recognized by the String..::.Trim method.)

Unicode name	Unicode code point	Remarks
CHARACTER TABULATION	U+0009
LINE FEED	U+000A
LINE TABULATION	U+000B
FORM FEED	U+000C
CARRIAGE RETURN	U+000D
SPACE	U+0020
NEXT LINE	U+0085	Introduced in the .NET Framework version 2.0.
NO-BREAK SPACE	U+00A0
OGHAM SPACE MARK	U+1680
EN QUAD	U+2000
EM QUAD	U+2001
EN SPACE	U+2002
EM SPACE	U+2003
THREE-PER-EM SPACE	U+2004
FOUR-PER-EM SPACE	U+2005
SIX-PER-EM SPACE	U+2006
FIGURE SPACE	U+2007
PUNCTUATION SPACE	U+2008
THIN SPACE	U+2009
HAIR SPACE	U+200A
ZERO WIDTH SPACE	U+200B	.NET Framework versions 1.0 and 1.1 only.
LINE SEPARATOR	U+2028
PARAGRAPH SEPARATOR	U+2029
IDEOGRAPHIC SPACE	U+3000

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.

For example:

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

Examples

The following example demonstrates how to extract individual words from a block of text by treating white space and punctuation marks as delimiters. The character array passed to the separator parameter of the String..::.Split(array<Char>[]()[]) method consists of a space character and a tab character, together with some common punctuation symbols.

Visual Basic

Public Class SplitTest
    Public Shared Sub Main()
        Dim words As String = "This is a list of words, with: a bit of punctuation" + _
                              vbTab + "and a tab character."
        Dim split As String() = words.Split(New [Char]() {" "c, ","c, "."c, ":"c, CChar(vbTab) })

        For Each s As String In  split
            If s.Trim() <> "" Then
                Console.WriteLine(s)
            End If
        Next s
    End Sub 'Main
End Class 'SplitTest
' The example displays the following output to the console:
'       This
'       is
'       a
'       list
'       of
'       words
'       with
'       a
'       bit
'       of
'       punctuation
'       and
'       a
'       tab
'       character

using System;

public class SplitTest {
    public static void Main() {

        string words = "This is a list of words, with: a bit of punctuation" +
                       "\tand a tab character.";

        string [] split = words.Split(new Char [] {' ', ',', '.', ':', '\t' });

        foreach (string s in split) {

            if (s.Trim() != "")
                Console.WriteLine(s);
        }
    }
}
// The example displays the following output to the console:
//       This
//       is
//       a
//       list
//       of
//       words
//       with
//       a
//       bit
//       of
//       punctuation
//       and
//       a
//       tab
//       character

Platforms

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune

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

Version Information