#! /usr/bin/perl
use strict;
use warnings;
my $x=1;
my @arr= qw(foo cho roh foo kho foo  moo foo);
foreach(@arr){print  $x++ if (/foo/)}

##</code><code>##

#! /usr/bin/perl
use strict;
use warnings;
my $x=1;
my @arr= qw(foo cho roh foo kho foo  moo foo);
my $str=join ' ',@arr;
$str=~ /foo/;
print $&; #### In place of $&; we can use that for no
          #### for no. of matches.