Regex to get string between number and underscore C#

Question

i'm tryng make a regex to get the string between some number and underscore, for example:

I have CP_01Ags_v5, so I need a regex to match just Ags. another example could be CP_13Hgo_v5 and match Hgo.

Some idea?

Answer 1

Based off the examples and matches you are describing. You want something along the lines of.

[0-9]+(.*)[_]

to break it down. The regex looking for any number that shows up one or more times then matches everything after the number(s) up until the [_] underscore.

The downfall is this assumes the examples you provided are similar. If your example is

CP_13Hgo_v5asdf_

then it will match

Hgo_v5asdf

---

if you have other possible findings then you want the non-greedy version of this regex.

[0-9]+(.*?)[_]

this will cause two groups to be found in this example

CP_13Hgo_v5asdf_

will find the following groups:

Hgo

and

asdf

Answer 2

You can use look-arounds to match just the string between the digits and the underscore e.g.

(?<=\d)[A-Za-z]+(?=_)

Demo on regex101

In C# (note the need to escape the \ in the regex):

String s = @"CP_01Ags_v5 CP_13Hgo_v5";
Match m = Regex.Match(s, "(?<=\\d)[A-Za-z]+(?=_)");
while (m.Success) {
    Console.WriteLine(m.Value);
    m = m.NextMatch();
}

Output

Ags
Hgo

Answer 3

If your string is always at least two characters and there are no other strings of at least two characters, then you can apply the following:

var text = "CP_01Ags_v5";
var x = Regex.Match(text, @"(?<!^)[A-Za-z]{2,}");

Answer 4

Use Regex Group:

(?<leftPart>_\d{2})(?<YourTarget>[a-zA-Z])(?<rightPart>_[a-zA-Z0-9]{2})

C#:

Regex re = new Regex(@"(?<leftPart>_\d{2})(?<YourTarget>[a-zA-Z])(?<rightPart>_[a-zA-Z0-9]{2})");

/*
* Loop
* To get value of group you want
*/
foreach (Match item in re.Matches("CP_01Ags_v5 CP_13Hgo_v5,"))
{
        Console.WriteLine(" Match: " + item.ToString());
        Console.WriteLine(" Your Target you want: " + item.Groups["YourTarget"]);        
}