Regular Expression to match everything that appears before a colon?

Question

I need to remove some data from an RSS feed.

It's everything that appears before a : and also preferably the space that appears just after the :

Example:

Hello : Charlie wants to know how to delete everything behind him from behind the colon and one space in front. I will always have this question mark on the end?

Where the : and hello would be matched but not the "Charlie said hello"

Thanks to all who have this wonderful knowledge and take time to reply.

Answer 1

Try this:

^[^:]+:\s?

The trailing \s? will match a space following the colon, but not require it.

I agree with @gpojd; you should use a negative character class to avoid greediness issues if there are colons in the payload.

Answer 2

You can use just: ^.*:

This matches:

Hello : Charlie wants to know how to delete everything behind him from behind the colon and one space in front. I will always have this question mark on the end?

Answer 3

Something like ^.*: * should work well. This matches from the beginning of the line up to the colon and any spaces after it.

Answer 4

Use

^[^:]+:\s*

instead of

^.+:\s*

This is an example of it working:

perl -le 'my $string = q{Foo : bar baz}; $string =~ s{^[^:]+:\s*}{}; print $string;'

And I recommended the first one over the second to avoid greediness issues:

perl -le 'my $string = q{Foo : bar: baz}; $string =~ s{^[^:]+:\s*}{}; print $string;'

To see the greediness issues I mentioned:

perl -le 'my $string = q{Foo : bar baz}; $string =~ s{^.+:\s*}{}; print $string;'
perl -le 'my $string = q{Foo : bar: baz}; $string =~ s{^.+:\s*}{}; print $string;'