Regular Expression for a middle string

Question

I need to extract from the below string

2_240219_0.vnd as 240219

I have tried as follows: _[0-9]+_

This gives me _240219_

How do I remove the _ from both ends.

Answer 1

I would actually recommend not even using regex in this case. A simple string split on underscore should do just fine:

string input = "2_240219_0.vnd";
string middle = input.Split('_')[1];
Console.WriteLine(middle);

240219

Answer 2

您可以尝试使用其他正则表达式： ([\\d]{6,})

Match m = Regex.Match(2_240219_0.vnd, `([\d]{6,})`, RegexOptions.IgnoreCase);