如何使用正则表达式从字符串中提取具有扩展名的单词？

Question

I need to extract a word from a string before an extension. Let's say I've got a string like :

"Hey Stackoverflow.xyz Whats up?"

I need to extract a word with extension .xyz ie Stackoverflow. How can this be achieved?

Answer 1

You can use positive look ahead to ensure the string you want to extract follows .xyz using this regex,

\S+(?=\.xyz)

Demo

Try these C# codes,

string str = "Hey Stackoverflow.xyz Whats up?";
var m = Regex.Match(str,@"\S+(?=\.xyz)");
Console.WriteLine(m.Groups[0].Value);

Outputs,

Stackoverflow

Online C# demo

In case you want to extract your string with extension Stackoverflow.xyz , just change the look ahead part of regex to normal string like this,

\S+\.xyz

Answer 2

/(\w+)\\.[^\W]+/

在regex101上玩

Answer 3

Use the following regex to extract the word you need before the extension

\s(.*)?\.

Here the word will be captured using the brackets.

string str = "Hey Stackoverflow.xyz Whats up?";
var regexResult = Regex.Match(str,@"\s(.*)?\.");
Console.WriteLine(regexResult.Groups[1].Value);