C# 是否有返回正则表达式匹配开始的索引的函数？
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Is there a function that returns index where RegEx match starts?
提问by Royson
I have strings of 15 characters long. I am performing some pattern matching on it with a regular expression. I want to know the position of the substring where the IsMatch()function returns true.
我有 15 个字符长的字符串。我正在使用正则表达式对其进行一些模式匹配。我想知道IsMatch()函数返回 true的子字符串的位置。
Question:Is there is any function that returns the index of the match?
问题：是否有任何函数可以返回匹配项的索引？
采纳答案by Adriaan Stander
For multiple matches you can use code similar to this:
对于多个匹配，您可以使用与此类似的代码：
Regex rx = new Regex("as");
foreach (Match match in rx.Matches("as as as as"))
{
int i = match.Index;
}
回答by spender
Instead of using IsMatch, use the Matchesmethod. This will return a MatchCollection, which contains a number of Matchobjects. These have a property Index.
使用Matches方法而不是使用 IsMatch 。这将返回一个MatchCollection，其中包含许多Match对象。这些有一个属性Index。
回答by Mark Byers
Use Match instead of IsMatch:
使用 Match 而不是 IsMatch：
Match match = Regex.Match("abcde", "c");
if (match.Success)
{
int index = match.Index;
Console.WriteLine("Index of match: " + index);
}
Output:
输出：
Index of match: 2
回答by YOU
Regex.Match("abcd", "c").Index
2
Note# Should check the result of Match.success, because its return 0, and can confuse with Position 0, Please refer to Mark Byers Answer. Thanks.
注意# 应该检查 Match.success 的结果，因为它返回 0，并且会与位置 0 混淆，请参考 Mark Byers Answer。谢谢。
回答by Paul Creasey
Console.Writeline("Random String".IndexOf("om"));
This will output a 4
这将输出一个 4
a -1 indicates no match
-1 表示不匹配
回答by Mitch Wheat
Rather than use IsMatch(), use Matches:
而不是使用IsMatch()，使用Matches：
const string stringToTest = "abcedfghijklghmnopqghrstuvwxyz";
const string patternToMatch = "gh*";
Regex regex = new Regex(patternToMatch, RegexOptions.Compiled);
MatchCollection matches = regex.Matches(stringToTest);
foreach (Match match in matches )
{
Console.WriteLine(match.Index);
}
