need to get everything after 2nd dash in string?

问题

I have string values like those below:

string str1 = "123-456-test";
string str1 = "123 - 456 - test-test";
string str1 = "123-REQ456-test";
string str1 = "123 - REQ456 - test-test";

I need to grab the entire content from string right after the 2nd dash.

I tried String.Split('-'), but it did not work. I think I need to use a regex, but I am not able to find a correct one. Please suggest.

回答1:

(?:[^-\n]+-){2}(.*)$

You can try this.Grab the capture.See demo.

https://regex101.com/r/tS1hW2/21

回答2:

This even easy with string methods like IndexOf and Substring.

string str1 = "123-456-test";
int secondIndex = str1.IndexOf('-', str1.IndexOf('-') + 1);
str1 = str1.Substring(secondIndex + 1); // test

回答3:

You can use LINQ Skip(2) with Split, no need to use a regex in C# for this task:

string input = "123-456-test";
string res = input.Contains("-") && input.Split('-').GetLength(0) > 2 ? string.Join("-", input.Split('-').Skip(2).ToList()) : input;

Result:

enter image description here

In case you want to use a regex by all means, you can leverage a variable-width look-behind in C#:

(?<=(?:-[^-]*){2}).+$

See regex demo

Sample code:

var rgx = new Regex(@"(?<=(?:-[^-]*){2}).+$");
Console.WriteLine(rgx.Match("123-456-test").Value);
Console.WriteLine(rgx.Match("123 - 456 - test-test").Value);
Console.WriteLine(rgx.Match("123-REQ456-test").Value);
Console.WriteLine(rgx.Match("123 - REQ456 - test-test").Value);

Output:

test
 test-test
test
 test-test

来源：https://stackoverflow.com/questions/30500975/need-to-get-everything-after-2nd-dash-in-string

标签

regex