Re^2: Check array for several matches

[Lotus1]

My approach was almost the same as yours except I used a function so I could short circuit and return as soon an item was determined to be missing.

use warnings;
use strict;
use Data::Dumper;

my @allwords = qw( mary had a little lamb its fleece was white as snow
+ );
my @checkwords = qw( little lamb fleece everywhere );

print "All words were ", check_array_for_words(\@allwords, \@checkword
+s) ? "" : "not ", "found.\n";

sub check_array_for_words {
    my ($ar_allwords, $ar_checkwords) = @_;
    
    my %hash;

    foreach (@$ar_allwords){
        $hash{$_} = undef;
    }
    print Dumper(\%hash);

    foreach (@$ar_checkwords) {
        if (not exists $hash{$_}) {
            return 0;
        }
    }
    return 1;
}

__END__
$VAR1 = {
          'had' => undef,
          'lamb' => undef,
          'a' => undef,
          'fleece' => undef,
          'little' => undef,
          'white' => undef,
          'as' => undef,
          'was' => undef,
          'mary' => undef,
          'snow' => undef,
          'its' => undef
        };
All words were not found.

[Marshall]

Yes, this will certainly work! I made an implicit assumption that there were very few check words (perhaps just 3) to be checked against perhaps a potentially very big list of other words. So I restricted my hash to be only the 3 checked words instead of all_words. But I think your code is just fine.

I don't think it is necessary to beat this thing to death in all its variations. I don't know whether I actually succeeded or not, but I was attempting to address the OP's comments about searching the internet for hours and copying code that he didn't understand and that didn't work for him.

I avoided map{} and grep{} (which are special kinds of foreach loops) and attempted to write very simple loops in the hope that the OP will take the time to understand them. I added a whole lot of verbiage in an attempt to explain an example of the algorithmic thought process. I am hoping that the OP learned not only a solution to this current problem, but also stuff that is helpful to future problems.

[Lotus1]

The short circuit thing doesn't add much for three items, that's true. Probably isn't a noticeable difference for anything less than 3,000 really. I had already written mine up before I noticed yours so it seemed fitting to put it with yours.