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Re: Comparing a value to hash key

by NetWallah (Abbot)
on Nov 14, 2012 at 04:53 UTC ( #1003750=note: print w/ replies, xml ) Need Help??


in reply to Comparing a value to hash key

Is it possible to check a variable against all the keys in a hash
The question suggests you do not understand the fundamental property of a hash.

The primary use of a hash is for a quick and simple lookup of a 'key', by indexing, using curly-braces.

The first line of your code:

if (! exists ($hash{$remoteIP})){
does exactly that - looks up the value of $remoteIP, and can be thought of as comparing with every possible key in %hash, and returning 'true' if the matching one exists.

Your later comparison:

if ($remoteIP ~~ @k){
is a more expensive way of doing the same comparison that the first line does.

             "By three methods we may learn wisdom: First, by reflection, which is noblest; Second, by imitation, which is easiest; and third by experience, which is the bitterest."           -Confucius


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