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Re: How to I check if a value is present in an array?

by moritz (Cardinal)
on Aug 03, 2013 at 10:54 UTC ( #1047694=note: print w/replies, xml ) Need Help??

in reply to How to I check if a value is present in an array?

grep doesn't do what you think. It returns a list of all elements where the search expression is true. The search expression in your case is $genes[$index], so if that's a true value, grep returns all the elements of @gl.

What you probably want to write instead is something like

for my $current (@genes) { if (grep { $_ eq $current } @gl) { print $current; } }

Though of course if either (or both) of these arrays is large, that is rather inefficient, and you might consider storing stuff in a hash in the first place.

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Re^2: How to I check if a value is present in an array?
by Tux (Abbot) on Aug 03, 2013 at 12:17 UTC

    If @gl is (or can be) large/huge, List::Util's first can be an important speedup.

    use List::Util qw( first ); for my $current (@genes) { say $current if first { $_ eq $current } @gl; }

    Enjoy, Have FUN! H.Merijn

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