How can I use the match variable $1 following a substitution in Perl?

Question

What is the cleanest way of picking up a match variable from a substitution in Perl I sometimes find myself writing

    s/(something)// ;
    my $x = $1 ;

then I realise that if the s/ / / fails $1 might be carrying over a value from a previous match. So I try

    my  $x = 'defaultvalue' ;
    if ( s/(something)// )
    {
     $x = $1 ;
    }

Is this the cleanest way of doing it?

Answer 1

TMTOWTDI.

The idiomatic Perl usually seen might be somthing like:

my $x='defaultvalue';

$x=$1 if (s/(something)//) ;

Answer 2

As others have pointed out, TIMTOWTDI.

I'd personnally wrap it up as a single expression, so as not to distract too much from the point:

my $x = s/(something)// ? $1 : 'defaultvalue';