firmament has asked for the wisdom of the Perl Monks concerning the following question:

I'm looking to remove some text within parantheses, thinking like this: 
my $s = "bla bla (parenthesis) somestring";
if  ($s =~ /.*(\(parenthesis\))\s*somestring/) {
        print "matched $1\n"; #this prints "(parenthesis)"
        $s =~ s/$1//;
        # $s now looks "bla bla () somestring" rather than the desired
+ "bla bla somestring"
}

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But even though $1 when printed includes the parenthesis, the substitution statement does not remove them. Am I missing something trivial (probably)? Many thanks.

Replies are listed 'Best First'.
Re: Remove text within parenthesis
by choroba (Cardinal) on May 07, 2013 at 22:11 UTC
    To avoid the interpretation of parentheses inside $1, use \Q: 
    $s =~ s/\Q$1//;

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    Note that this is still not the desired "bla bla somestring" because there are two spaces after the bla bla.

    لսႽ† ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ
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      Thanks a lot for the \Q advice, very interesting.
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Re: Remove text within parenthesis
by gurpreetsingh13 (Scribe) on May 08, 2013 at 03:52 UTC
    Or just a simple regex should work. What about this? 
    $s =~ s/(.*)\s(\(.*\))\s(.*)/$1 $3/g;
print "matched $2\n";
print $s;

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Re: Remove text within parenthesis
by jnyman (Acolyte) on May 08, 2013 at 12:06 UTC
    If you have nested parentheses, the solution is somewhat more complex: 
    use 5.014;

my $s = "a (d (b) (e (f) ) ) c";
say remove_par($s);

sub remove_par {
    my ( $result, $open );
    foreach my $ch ( split // => shift ) {        
        $open++ if $ch eq '(';
        $open-- if $ch eq ')';
        $result .= $ch if !$open && $ch ne ')';
    }
    die "non-matching parentheses" if $open;
    return $result;
};

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Re: Remove text within parenthesis
by Anonymous Monk on May 07, 2013 at 22:14 UTC
    Try  $s =~ s{ \(parenthesis\) }{}x;
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