in reply to how to quickly tell if number is in an array

The methods shown so far are best if the test only occurs a few times in the program and if the list is short. For frequent use, make a hash with the array elements as keys, and check for existence of the test value as a key.

my @array = (1,2,5..20,42..99);
my %element;
@element{@array} = ();
print exists $element{$num}? "$num found": "$num not found";

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Re^2: how to quickly tell if number is in an array
by sauoq (Abbot) on Oct 13, 2005 at 01:26 UTC
    For frequent use, make a hash

    Yes. (But don't do this with refs.) There are compromises too, like binary searches and Tie::IxHash and other modules. Lots of different trade-offs can be made between ordering restrictions, code complexity, execution time, and space requirements. The trick is picking the right one. :-)

    -sauoq
"My two cents aren't worth a dime.";
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