正则表达式 C# - 是否可以在匹配时提取匹配项？
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Regular expressions C# - is it possible to extract matches while matching?
提问by sarsnake
Say, I have a string that I need to verify the correct format of; e.g. RR1234566-001(2 letters, 7 digits, dash, 1 or more digits). I use something like:
说，我有一个字符串，我需要验证其格式是否正确；例如RR1234566-001（2 个字母、7 个数字、破折号、1 个或多个数字）。我使用类似的东西：
Regex regex = new Regex(patternString);
if (regex.IsMatch(stringToMatch))
{
return true;
}
else
{
return false;
}
This works to tell me whether the stringToMatchfollows the pattern defined by patternString. What I need though (and I end up extracting these later) are:
123456and 001-- i.e. portions of the stringToMatch.
这可以告诉我 是否stringToMatch遵循patternString. 不过，我需要的是（我最终会在稍后提取这些内容）是：
123456和001- 即stringToMatch.
Please note that this is NOT a question about how to construct regular expressions. What I am asking is: "Is there a way to match and extract values simultaneously without having to use a split function later?"
请注意，这不是关于如何构造正则表达式的问题。我要问的是：“有没有一种方法可以同时匹配和提取值，而不必稍后使用拆分函数？”
采纳答案by Andomar
You can use regex groups to accomplish that. For example, this regex:
您可以使用正则表达式组来实现这一点。例如，这个正则表达式：
(\d\d\d)-(\d\d\d\d\d\d\d)
Let's match a telephone number with this regex:
让我们用这个正则表达式匹配一个电话号码：
var regex = new Regex(@"(\d\d\d)-(\d\d\d\d\d\d\d)");
var match = regex.Match("123-4567890");
if (match.Success)
....
If it matches, you will find the first three digits in:
如果匹配，您将在以下位置找到前三位数字：
match.Groups[1].Value
And the second 7 digits in:
和第二个 7 位数字：
match.Groups[2].Value
P.S. In C#, you can use a @"" style string to avoid escaping backslashes. For example, @"\hi\" equals "\\hi\\". Useful for regular expressions and paths.
PS 在 C# 中，您可以使用 @"" 样式字符串来避免转义反斜杠。例如，@"\hi\" 等于 "\\hi\\"。对正则表达式和路径很有用。
P.S.2. The first group is stored in Group[1], not Group[0] as you would expect. That's because Group[0] contains the entire matched string.
PS2。第一个组存储在 Group[1] 中，而不是您期望的 Group[0] 中。这是因为 Group[0] 包含整个匹配的字符串。
回答by cyberconte
Use grouping and Matches instead.
改用分组和匹配。
I.e.:
IE：
// NOTE: pseudocode.
Regex re = new Regex("(\d+)-(\d+)");
Match m = re.Match(stringToMatch))
if (m.Success) {
String part1 = m.Groups[1].Value;
String part2 = m.Groups[2].Value;
return true;
}
else {
return false;
}
You can also name the matches, like this:
您还可以命名匹配项，如下所示：
Regex re = new Regex("(?<Part1>\d+)-(?<Part2>\d+)");
and access like this
并像这样访问
String part1 = m.Groups["Part1"].Value;
String part2 = m.Groups["Part2"].Value;
回答by LukeH
You can use parentheses to capture groups of characters:
您可以使用括号来捕获字符组：
string test = "RR1234566-001";
// capture 2 letters, then 7 digits, then a hyphen, then 1 or more digits
string rx = @"^([A-Za-z]{2})(\d{7})(\-)(\d+)$";
Match m = Regex.Match(test, rx, RegexOptions.IgnoreCase);
if (m.Success)
{
Console.WriteLine(m.Groups[1].Value); // RR
Console.WriteLine(m.Groups[2].Value); // 1234566
Console.WriteLine(m.Groups[3].Value); // -
Console.WriteLine(m.Groups[4].Value); // 001
return true;
}
else
{
return false;
}
回答by sahil gupta
string text = "RR1234566-001";
string regex = @"^([A-Z a-z]{2})(\d{7})(\-)(\d+)";
Match mtch = Regex.Matches(text,regex);
if (mtch.Success)
{
Console.WriteLine(m.Groups[1].Value);
Console.WriteLine(m.Groups[2].Value);
Console.WriteLine(m.Groups[3].Value);
Console.WriteLine(m.Groups[4].Value);
return true;
}
else
{
return false;
}
