After the grep how would I remove the entries in @bad_matches from @array before the next $x? Would this be faster?

Are you trying to match only the items in @array that match all of your regexes? If so, then I would probably write the loops with the outer one as foreach @regex (since @regex is much smaller) .. Please correct me if I misinterpreted your question. 

foreach $reg (@regex) {
    
    my $i = 0;
    while ($i <= $#array) {
        if ($array[$i] =~ /$x/) {
            # successful, so keep $array[$i] in array and move to the 
+next
            $i++;
        } else {
            # this item didn't pass so we remove it for good and
            # never have to test it again.
            splice(@array, $i, 1); 
        }
    }

}

[download]
Something like this might improve your efficiency -- as soon as an item fails a test, it is removed from @array, so we have less and less to loop through each time. Ideally you would want to organize @regex so that the most restrictive expressions (those that fail on the highest number of items in @array) come first -- that would give you the best efficiency.

Let me know if this is not what you intended for this code snippet.

blokhead

In reply to Re: Efficiency: Foreach loop and multiple regexs by blokhead
in thread Efficiency: Foreach loop and multiple regexs by neilwatson

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