David B David B - 2 months ago 7
Perl Question

How do I use Perl's smart matching to match many patterns at once?

I was trying to follow some examples to use smart matching in the following piece of code, but failed (nothing was filtered out). How can I use smart matching here to match against multiple regexes at once?

my $regexes_to_filter_a = ("tmp", "temp", "del")
my @organism_dirs = (); # this will hold final list of dirs to processs

my @subdirs = File::Find::Rule->directory->maxdepth(1)->in($root_dir);
foreach my $subdir (@subdirs) {
my $filter = 0;

# IMPROVE: can do smart matching here
foreach my $regex ( @{$regexes_to_filter_a} ) {
if ( basename($subdir) =~ $regex ) {
$filter = 1; # filter out this dir
last;
}
}

unless ($filter) {
push @organism_dirs, $subdir;
}
}

Answer

Here is a quick untested change to your example:

my @regexes_to_filter_a = (qr/^tmp$/, qr/^temp/, qr/del/);
my @organism_dirs = (); # this will hold final list of dirs to processs

my @subdirs = File::Find::Rule->directory->maxdepth(1)->in($root_dir);
foreach my $subdir (@subdirs) {

    unless (basename($subdir) ~~ @regexes_to_filter_a) {
        push @organism_dirs, $subdir;
    }
}

The key changes are:

i) should be either @array = (...list...); or $array_ref = [...list...];

my @regexes_to_filter_a = ("tmp", "temp", "del");

ii) and change to using smart match. Below checks that basename($subdir) is in (~~) the @regexes_to_filter_a array. So no need to loop through the array and do individual regex checks.

unless (basename($subdir) ~~ @regexes_to_filter_a) { ... }

/I3az/

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