regexperl

Perl special variables for regex matches

I'd like to use one of perl's special variable to make this snippet a bit less large and ugly:

my $mysqlpass = "mysqlpass=verysecret";
$mysqlpass = first { /mysqlpass=/ } @vars;
$mysqlpass =~ s/mysqlpass=//;

I have looked this info up and tried several special variables ($',$1,$`, etc) to no avail

Solution

  • A s/// will return true if it replaces something.

    Therefore, it is possible to simply combine those two statements instead of having a redundant m//:

    use strict;
use warnings;

use List::Util qw(first);

chomp(my @vars = <DATA>);

my $mysqlpass = first { s/mysqlpass=// } @vars;

print "$mysqlpass\n";

__DATA__
mysqluser=notsosecret
mysqlpass=verysecret
mysqldb=notsecret

    Outputs:

    verysecret

    One Caveat

    Because $_ is an alias to the original data structure, the substitution will effect the @vars value as well.

    Alternative using split

    To avoid that, I would inquire if the @vars contains nothing but key value pairs separated by equal signs. If that's the case, then I would suggest simply translating that array into a hash instead.

    This would enable much easier pulling of all keys:

    use strict;
use warnings;

chomp(my @vars = <DATA>);

my %vars = map {split '=', $_, 2} @vars;

print "$vars{mysqlpass}\n";

__DATA__
mysqluser=notsosecret
mysqlpass=verysecret
mysqldb=notsecret

    Outputs:

    verysecret