返回从正则表达式匹配只有一部分 [英] Returning only part of match from Regular Expression

问题描述

说我有字符串用户名：firstname.surname？包含在一个较大的字符串我该如何使用正则表达式来刚拿到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?

每一个方法我都试过返回字符串用户名：firstname.surname那我必须做一个字符串替换上的用户名：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.

难道反向引用是使用此处

Could back references be of use here?

编辑：

较长的字符串可以包含帐户名：firstname.surname所以我为什么要匹配的用户名：藏汉字符串的一部分只得到了价值

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;
}

把<东西> 在一组括号中的开头（如（LT;东西> ...）），使您可以获取使用从匹配值的东西作为一个键（例如：从 m.Groups [东西。值）

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)

如果你不想去命名您的群体的麻烦，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;
}

和刚刚获得匹配的第一件事。 （请注意，第一个括号组是指数 1 ;匹配整个表达式为指数 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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