' Declare object variable of type Regex.
Dim r As Regex
' Create a Regex object and define its regular expression.
r = New Regex("/s2000")
C#
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// Declare object variable of type Regex.
Regex r;
// Create a Regex object and define its regular expression.
r = new Regex("//s2000");
Match
Match
类表示正则表达式匹配操作的结果。下面的示例使用 Regex 类的 Match 方法返回 Match 类型的对象，以便找到输入字符串中的第一个匹配项。此示例使用 Match 类的
Match.Success
属性来指示是否已找到匹配。
Visual Basic
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' cCreate a new Regex object.
Dim r As New Regex("abc")
' Find a single match in the input string.
Dim m As Match = r.Match("123abc456")
If m.Success Then
' Print out the character position where a match was found.
' (Character position 3 in this case.)
Console.WriteLine("Found match at position " & m.Index.ToString())
End If
C#
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// Create a new Regex object.
Regex r = new Regex("abc");
// Find a single match in the string.
Match m = r.Match("123abc456");
if (m.Success)
{
// Print out the character position where a match was found.
// (Character position 3 in this case.)
Console.WriteLine("Found match at position " + m.Index);
}
Dim mc As MatchCollection
Dim results(20) As String
Dim matchposition(20) As Integer
' Create a new Regex object and define the regular expression.
Dim r As New Regex("abc")
' Use the Matches method to find all matches in the input string.
mc = r.Matches("123abc4abcd")
' Loop through the match collection to retrieve all
' matches and positions.
Dim i As Integer
For i = 0 To mc.Count - 1
' Add the match string to the string array.
results(i) = mc(i).Value
' Record the character position where the match was found.
matchposition(i) = mc(i).Index
Next i
C#
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MatchCollection mc;
String[] results = new String[20];
int[] matchposition = new int[20];
// Create a new Regex object and define the regular expression.
Regex r = new Regex("abc");
// Use the Matches method to find all matches in the input string.
mc = r.Matches("123abc4abcd");
// Loop through the match collection to retrieve all
// matches and positions.
for (int i = 0; i < mc.Count; i++)
{
// Add the match string to the string array.
results[i] = mc[i].Value;
// Record the character position where the match was found.
matchposition[i] = mc[i].Index;
}
Imports System
Imports System.Text.RegularExpressions
Public Class RegexTest
Public Shared Sub RunTest()
' Define groups "abc", "ab", and "b".
Dim r As New Regex("(a(b))c")
Dim m As Match = r.Match("abdabc")
Console.WriteLine("Number of groups found = " _
& m.Groups.Count.ToString())
End Sub
Public Shared Sub Main()
RunTest()
End Sub
End Class
C#
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using System;
using System.Text.RegularExpressions;
public class RegexTest
{
public static void RunTest()
{
// Define groups "abc", "ab", and "b".
Regex r = new Regex("(a(b))c");
Match m = r.Match("abdabc");
Console.WriteLine("Number of groups found = " + m.Groups.Count);
}
public static void Main()
{
RunTest();
}
}
该示例产生下面的输出。
Visual Basic
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Number of groups found = 3
C#
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Number of groups found = 3
CaptureCollection
CaptureCollection
类表示捕获的子字符串的序列，并且返回由单个捕获组执行的捕获的集合。由于限定符，捕获组可以在单个匹配中捕获多个字符串。Captures 属性（CaptureCollection 类的对象）是作为
Match
和
group
类的成员提供的，以便于对捕获的子字符串的集合的访问。
例如，如果使用正则表达式 ((a(b))c)+（其中 + 限定符指定一个或多个匹配）从字符串“abcabcabc”中捕获匹配，则子字符串的每一匹配的 Group 的 CaptureCollection 将包含三个成员。
Imports System
Imports System.Text.RegularExpressions
Public Class RegexTest
Public Shared Sub RunTest()
Dim counter As Integer
Dim m As Match
Dim cc As CaptureCollection
Dim gc As GroupCollection
' Look for groupings of "Abc".
Dim r As New Regex("(Abc)+")
' Define the string to search.
m = r.Match("XYZAbcAbcAbcXYZAbcAb")
gc = m.Groups
' Print the number of groups.
Console.WriteLine("Captured groups = " & gc.Count.ToString())
' Loop through each group.
Dim i, ii As Integer
For i = 0 To gc.Count - 1
cc = gc(i).Captures
counter = cc.Count
' Print number of captures in this group.
Console.WriteLine("Captures count = " & counter.ToString())
' Loop through each capture in group.
For ii = 0 To counter - 1
' Print capture and position.
Console.WriteLine(cc(ii).ToString() _
& " Starts at character " & cc(ii).Index.ToString())
Next ii
Next i
End Sub
Public Shared Sub Main()
RunTest()
End Sub
End Class
C#
复制代码
using System;
using System.Text.RegularExpressions;
public class RegexTest
{
public static void RunTest()
{
int counter;
Match m;
CaptureCollection cc;
GroupCollection gc;
// Look for groupings of "Abc".
Regex r = new Regex("(Abc)+");
// Define the string to search.
m = r.Match("XYZAbcAbcAbcXYZAbcAb");
gc = m.Groups;
// Print the number of groups.
Console.WriteLine("Captured groups = " + gc.Count.ToString());
// Loop through each group.
for (int i=0; i < gc.Count; i++)
{
cc = gc[i].Captures;
counter = cc.Count;
// Print number of captures in this group.
Console.WriteLine("Captures count = " + counter.ToString());
// Loop through each capture in group.
for (int ii = 0; ii < counter; ii++)
{
// Print capture and position.
Console.WriteLine(cc[ii] + " Starts at character " +
cc[ii].Index);
}
}
}
public static void Main() {
RunTest();
}
}
此示例返回下面的输出结果。
Visual Basic
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Captured groups = 2
Captures count = 1
AbcAbcAbc Starts at character 3
Captures count = 3
Abc Starts at character 3
Abc Starts at character 6
Abc Starts at character 9
C#
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Captured groups = 2
Captures count = 1
AbcAbcAbc Starts at character 3
Captures count = 3
Abc Starts at character 3
Abc Starts at character 6
Abc Starts at character 9
组
group
类表示来自单个捕获组的结果。因为 Group 可以在单个匹配中捕获零个、一个或更多的字符串（使用限定符），所以它包含 Capture 对象的集合。因为 Group 继承自 Capture，所以可以直接访问最后捕获的子字符串（Group 实例本身等价于 Captures 属性返回的集合的最后一项）。
Group 的实例是由 Match.Groups(groupnum) 属性返回的，或者在使用“(?<groupname>)”分组构造的情况下，是由 Match.Groups("groupname") 属性返回的。
下面的代码示例使用嵌套的分组构造来将子字符串捕获到组中。
Visual Basic
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Dim matchposition(20) As Integer
Dim results(20) As String
' Define substrings abc, ab, b.
Dim r As New Regex("(a(b))c")
Dim m As Match = r.Match("abdabc")
Dim i As Integer = 0
While Not (m.Groups(i).Value = "")
' Copy groups to string array.
results(i) = m.Groups(i).Value
' Record character position.
matchposition(i) = m.Groups(i).Index
i = i + 1
End While
C#
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int[] matchposition = new int[20];
String[] results = new String[20];
// Define substrings abc, ab, b.
Regex r = new Regex("(a(b))c");
Match m = r.Match("abdabc");
for (int i = 0; m.Groups[i].Value != ""; i++)
{
// Copy groups to string array.
results[i]=m.Groups[i].Value;
// Record character position.
matchposition[i] = m.Groups[i].Index;
}
下面的示例在 Group 集合中循环，从 Group 的每一成员中提取 Capture 集合，并且将变量 posn 和 length 分别分配给找到每一字符串的初始字符串中的字符位置，以及每一字符串的长度。
Visual Basic
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Dim r As Regex
Dim m As Match
Dim cc As CaptureCollection
Dim posn, length As Integer
r = New Regex("(abc)*")
m = r.Match("bcabcabc")
Dim i, j As Integer
i = 0
While m.Groups(i).Value <> ""
' Grab the Collection for Group(i).
cc = m.Groups(i).Captures
For j = 0 To cc.Count - 1
' Position of Capture object.
posn = cc(j).Index
' Length of Capture object.
length = cc(j).Length
Next j
i += 1
End While
C#
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Regex r;
Match m;
CaptureCollection cc;
int posn, length;
r = new Regex("(abc)*");
m = r.Match("bcabcabc");
for (int i=0; m.Groups[i].Value != ""; i++)
{
// Capture the Collection for Group(i).
cc = m.Groups[i].Captures;
for (int j = 0; j < cc.Count; j++)
{
// Position of Capture object.
posn = cc[j].Index;
// Length of Capture object.
length = cc[j].Length;
}
}
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