仅从正则表达式返回匹配的一部分 [英] Returning only part of match from Regular Expression

问题描述

假设我在一个更大的字符串中包含字符串User Name:firstname.surname"，我该如何使用正则表达式来获取 firstname.surname 部分?

Say I have the string "User Name:firstname.surname" contained in a larger string how can I use a regular expression to just get the firstname.surname part?

我尝试过的每种方法都会返回字符串用户名:名字.姓氏"，然后我必须将用户名:"的字符串替换为空字符串.

Every method i have tried returns the string "User Name:firstname.surname" then I have to do a string replace on "User Name:" to an empty string.

在这里可以使用反向引用吗?

Could back references be of use here?

较长的字符串可能包含Account Name: firstname.surname"，因此我想匹配字符串的User Name:"部分以获取该值.

The longer string could contain "Account Name: firstname.surname" hence why I want to match the "User Name:" part of the string aswell to just get that value.

推荐答案

我喜欢使用命名组:

Match m = Regex.Match("User Name:first.sur", @"User Name:(?<name>w+.w+)");
if(m.Success)
{
   string name = m.Groups["name"].Value;
}

将 ? 放在括号中的组开头(例如 (?<something>...))允许您获得使用 something 作为键的匹配值(例如来自 m.Groups["something"].Value)

Putting the ?<something> at the beginning of a group in parentheses (e.g. (?<something>...)) allows you to get the value from the match using something as a key (e.g. from m.Groups["something"].Value)

如果你不想麻烦地命名你的组，你可以说

If you didn't want to go to the trouble of naming your groups, you could say

Match m = Regex.Match("User Name:first.sur", @"User Name:(w+.w+)");
if(m.Success)
{
   string name = m.Groups[1].Value;
}

然后获取匹配的第一件事.(请注意，第一个括号中的组位于索引 1；匹配的整个表达式位于索引 0)

and just get the first thing that matches. (Note that the first parenthesized group is at index 1; the whole expression that matches is at index 0)

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