#!/usr/bin/perl
use strict;
use warnings;

my @requiredMatches = ('word1', 'word2', 'word3');
my @testArray = qw (word2 abc word3 xyz word2 asdf word1 word2);

my %requiredMatches;

# set up a hash table to count occurences of
# each word that is required to be there.
# Start with "zero", haven't seen it yet.

foreach my $requiredWord (@requiredMatches)
{
   $requiredMatches{$requiredWord}=0;
}

# Now for each word in the input @testArray, increment it's
# "seen" count, if and only if it is one of the words
# that is being "tracked" meaning that a hash entry exists in
# %requiredMatches for that word, i.e., $requiredMatches{$word}
#
# If you don't check for "exists", Perl will happily create a new
# hash entry that is incremented. We don't want that here.
# We only want the %requiredMatches hash to contain only the
# "must have" words. Update: Well the "if" is not absolutely
# required below because we are only going to count "zeroes",
# but I prefer this formulation that doesn't generate unnessary
# hash entries.

foreach my $word (@testArray)
{
   $requiredMatches{$word}++ if exists $requiredMatches{$word};
}

# If every hash table entry got incremented (no zero initial
# values left), then every required Word was seen at least once.

my $countWordMissing=0;

foreach my $requiredWord (keys %requiredMatches)
{
   $countWordMissing++ if ($requiredMatches{$requiredWord} == 0);
}

print "testArray contains all words\n" if $countWordMissing==0;