#!/usr/local/bin/perl -w

use strict;

my @data = qw(analysis data power seek true);

my @keywd = qw(analysis analyzing applications co-principal
    completed computer computing consulting data
    );

for my $element (@data) {
    for my $i (0 .. $#keywd) {
        if ($element =~ m/$keywd[$i]/i) {
            print "$i\n";
        }
    }
}

##</code><code>##

0
8

##</code><code>##

...
my %keywdHash;

@keywdHash{@keywd}= (); # Use a hash slice to initialise the hash

for my $element (@data) {
    if (exists $keywdHash{lc $element}) {
        print "$element\n";
    }
}

##</code><code>##

analysis
data