Question

I have a CSV file that I use split to parse into an array of N items, where N is a multiple of 3.

Is there a way i can do this

foreach my ( $a, $b, $c ) ( @d ) {}

similar to Python?

Answer 1

You can use List::MoreUtils::natatime. From the docs:

my @x = ('a' .. 'g');
my $it = natatime 3, @x;
while (my @vals = $it->()) {
    print "@vals\n";
}

natatime is implemented in XS so you should prefer it for efficiency. Just for illustration purposes, here is how one might implement a three element iterator generator in Perl:

#!/usr/bin/perl

use strict; use warnings;

my @v = ('a' .. 'z' );

my $it = make_3it(\@v);

while ( my @tuple = $it->() ) {
    print "@tuple\n";
}

sub make_3it {
    my ($arr) = @_;
    {
        my $lower = 0;
        return sub {
            return unless $lower < @$arr;
            my $upper = $lower + 2;
            @$arr > $upper or $upper = $#$arr;
            my @ret = @$arr[$lower .. $upper];
            $lower = $upper + 1;
            return @ret;
        }
    }
}