c# split string by underscore

user_14033262 0
Viewed 53

I am working on some string generator task. I have some sample string duplicate_config_dev_V2 and I want to get output duplicate_config_dev. If input is duplicate_config_dev_V3 then I want to get duplicate_config_dev. I tried as below.

int countUnderScore = input.Count(c => c == '_');
if(countUnderScore > 0 )
{
    input = input.Split('_')[countUnderScore-1];
}

This code returns Dev as output but I want to return duplicate_config_dev.

.net-core c#
3 Answers

You can solve this problem using String.Split() like you have started, but that means you will have to re-assembly the parts of the string.

Instead I would use .LastIndexOf() to find the index of the last underscore in the string, and then use .Substring() to get rid of it.

String.LastIndexOf()

String.SubString()

user_8312110

If you want to remove the part after the last underscore, you can use the LastIndexOf method:

var input = "duplicate_config_dev_V2";
var index = input.LastIndexOf("_");
if (index >= 0)
  Console.WriteLine(input.Substring(0, index));

Output of above sample:

duplicate_config_dev
user_6425790

I'd very much consider using Regex here. It seems important that the string ends with _V# (# is some number).

This works:

var input = "duplicate_config_dev_V2";
var regex = new Regex(@"^(.*)_V\d+$");
var match = regex.Match(input);
if (match.Success)
    Console.WriteLine(match.Groups[1].Value);
user_2597690
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