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I have two arrays. The first array contains several strings. The second array contains elements, each of which might be a substring of an element in the first array.

Now I want to figure out which of the elements of the first array match the substrings in the 2nd array and do something with the other elements of the 1st array.

My code:

#!/usr/bin/perl use strict; my @array = ("foo {abc123}\n", "bar {def456}\n", "baz {ghi789}\n"); my @array2 = ("foo", "bar", "quux"); foreach my $i (@array) { chomp $i; print "checking $i\n"; if ($i =~ m/@array2/) { print "$i is in array2 - skipping\n"; next; } # Do something with $i now. }

Of course that didn't work

So I then tried adding this before the loop:

my $regex = "("; foreach (@array2) { $regex .= $_ . "|"; } $regex .= ")";
and then changing the if to:
if ($i =~ m/$regex/) {

And that matched every element although it shouldn't have matched the last one (I really am perplexed by this)

So now I'm at my last resort and putting an inner loop which goes through array2 and checks each element

#!/usr/bin/perl use strict; my @array = ("foo {abc123}\n", "bar {def456}\n", "baz {ghi789}\n"); my @array2 = ("foo", "bar", "quux"); OUTTER: foreach my $i (@array) { chomp $i; print "checking $i\n"; foreach my $j (@array2) { if ($i =~ m/$j/) { print "$i is in array2 (matches $j) - skipping\n"; next OUTTER; } } print "$i IS NOT IN ARRAY 2\n"; # Do something with $i now. }

So is this really the only way to do it? I can forsee having a very very very large array2 in the not too distant future. I don't think this code will scale well with that (plus the extra loop to me makes the code hard to read). Anyway just hoping there's a better way.

Thanks in advance

Edit:Thanks to everyone who found the problem with the $regex


In reply to regex with arrays and variables by xorl

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