Question

I want to write a regex to substitute remove white spaces within my string as follows:

String : user1: group user2 :group2 user3 : group3
to

user1:group user2:group2 user3:group3

What I tried so far is:

$argument =~ s/\s+\:/\:/g;

Answer 1

You are nearly there:

$argument =~ s/\s*:\s*/:/g;

There is no need to escape the :, and you want to search for whitespace both before and after the colon. Instead of \s+ which searches for one or more, I used \s* which searches for zero or more. That way you will match if there are no spaces before but some after, or vice-versa.