Since, as you say, your 'collections' are strings, you could consider something like the following:

my @required = qw ( apple banana orange pear );

my @collections = (
  'foo pear bar apple',
  'apple foo pear orange banana',
  'pineapple appearance',
);

foreach my $collection ( @collections ) {
  foreach my $item ( @required ) {
    $collection .= " $item" unless $collection =~ /\b$item\b/;
  }
}

print "$_\n" for @collections;

[download]

Update: ikegami++ (see below). I haven't changed the code in this node, but please use the suggested improvement.

In reply to Re: are they all there? by Not_a_Number
in thread are they all there? by anadem

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