add the element number to the array slice, and update the equal-to count number.

Whenever a single change requires two (or more) synchronised updates to the code, this is a bug waiting to happen.

In this case, we can take advantage of the fact that “all x are y” is logically equivalent to “it is not the case that any x is not y.” That is, we can eliminate the duplication by negating both the condition and the if statement:

use strict;
use warnings;

my @array = qw( 0 0 7 abc 0 );

for my $i ([0, 1, 4], [0, 1, 3, 4], [1], [], [2])
{
    print "(@array[ @$i ]): ";

    if (grep !/^0$/, @array[ @$i ])  # !/^0$/ would be better as $_ ne
+ '0'
    {
        print "not all are zero\n";
    }
    else
    {
        print "all are zero\n";
    }
}
[download]

Output:

 1:40 >perl 1692_SoPW.pl
(0 0 0): all are zero
(0 0 abc 0): not all are zero
(0): all are zero
(): all are zero
(7): not all are zero

 1:40 >
[download]

Hope that helps,