Articolo
11/18/2011

Strings.Split Method

Microsoft Silverlight will reach end of support after October 2021. Learn more.

Returns a zero-based, one-dimensional array containing a specified number of substrings.

Namespace: Microsoft.VisualBasic
Assembly: Microsoft.VisualBasic (in Microsoft.VisualBasic.dll)

Syntax

'Declaration
Public Shared Function Split ( _
    Expression As String, _
    Delimiter As String, _
    Limit As Integer, _
    Compare As CompareMethod _
) As String()

public static string[] Split(
    string Expression,
    string Delimiter,
    int Limit,
    CompareMethod Compare
)

Parameters

Expression
Type: System.String
Required. String expression containing substrings and delimiters.

Delimiter
Type: System.String
Optional. Any single character used to identify substring limits. If Delimiter is omitted, the space character (" ") is assumed to be the delimiter.

Limit
Type: System.Int32
Optional. Maximum number of substrings into which the input string should be split. The default, –1, indicates that the input string should be split at every occurrence of the Delimiter string.

Compare
Type: Microsoft.VisualBasic.CompareMethod
Optional. Numeric value indicating the comparison to use when evaluating substrings. See "Settings" for values.

Return Value

Type: array<System.String[]
String array. If Expression is a zero-length string (""), Split returns a single-element array containing a zero-length string. If Delimiter is a zero-length string, or if it does not appear anywhere in Expression, Split returns a single-element array containing the entire Expression string.

Remarks

By default, or when Limit equals -1, the Split function splits the input string at every occurrence of the delimiter string, and returns the substrings in an array. When the Limit parameter is greater than zero, the Split function splits the string at the first Limit-1 occurrences of the delimiter, and returns an array with the resulting substrings. For example, Split("a:b:c", ":") returns the array {"a", "b", "c"}, while Split("a:b:c", ":", 2) returns the array {"a", "b:c"}.

When the Split function encounters two delimiters in a row, or a delimiter at the beginning or end of the string, it interprets them as surrounding an empty string (""). For example, Split("xx", "x") returns the array containing three empty strings: one from between the beginning of the string and the first "x", one from between the two "x" strings, and one from between the last "x" and the end of the string.

This table demonstrates how the optional Delimiter, Limit, and Compare parameters can change the behavior of the Split function.

Split Call	Return Value
Split("42, 12, 19")	{"42," , "12," , "19"}
Split("42, 12, 19", ", ")	{"42", "12", "19"}
Split("42, 12, 19", ", ", 2)	{"42", "12, 19"}
Split("192.168.0.1", ".")	{"192", "168", "0", "1"}
Split("Alice and Bob", " AND ")	{"Alice and Bob"}
Split("Alice and Bob", " AND ", ,CompareMethod.Text)	{"Alice", "Bob"}
Split("someone@example.com", "@",1)	{"someone@example.com"}
Split("someone@example.com", "@",2)	{"someone", "example.com"}

The Compare argument can have the following values.

Constant	Description	Value
CompareMethod.Binary	Performs a binary comparison	0
CompareMethod.Text	Performs a textual comparison	1

Examples

The following example demonstrates how to split a string at its spaces.

Dim TestString As String = "Look at these!"
' Returns an array containing "Look", "at", and "these!".
Dim TestArray() As String = Split(TestString)

The following example demonstrates how to split strings with multiple delimiters in a row and filter out the empty strings.

Dim TestString As String = "apple    pear banana  "
Dim TestArray() As String = Split(TestString)
' TestArray holds {"apple", "", "", "", "pear", "banana", "", ""}
Dim LastNonEmpty As Integer = -1
For i As Integer = 0 To TestArray.Length - 1
    If TestArray(i) <> "" Then
        LastNonEmpty += 1
        TestArray(LastNonEmpty) = TestArray(i)
    End If
Next
ReDim Preserve TestArray(LastNonEmpty)
' TestArray now holds {"apple", "pear", "banana"}

Version Information

Silverlight

Supported in: 5, 4, 3

Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

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