Re: Request help on optimizing a loop for looking up numbers

Hi, if I understood correctly your problem you could just create a hash whose keys are made of the concatenated start and end, with a appropriate separator, e.g. "7-12". The values can be anything, it could be 1. Then you just check for the existence of the hash for the concatenated pair of numbers.

if (exists $hash{"start-$end"} ) {
    # do something
}
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Re^2: Request help on optimizing a loop for looking up numbers by VincentK (Beadle) on Dec 11, 2013 at 16:16 UTC
Thank you for your reply Laurent_R. That is close to what I want. Again, I probably did not do a good enough job explaining what I want. Sorry. The look up you have is close, but I want a check similar to yours that will check for the numbers between the range. Given '7-12', the code will check for 7,8,9,10,11, and 12. Is there something I can use that is similar to your check, but will essentially look for this ? `if ( exists $hash{7} \|\| exists $hash{8}... exists $hash{12} )` Ideally `if ( exists $hash{7..12} )` Thanks.	[reply] [d/l] [select]
Re^3: Request help on optimizing a loop for looking up numbers by Laurent_R (Canon) on Dec 11, 2013 at 16:49 UTC
Hash slices might be what you need. This is an example of how they work demonstrated under the Perl debugger: `DB<1> @hash{qw/one two three/} = qw /1 2 3/; DB<2> x \%hash 0 HASH(0x302ee308) 'one' => 1 'three' => 3 'two' => 2 DB<3>` [download]	[reply] [d/l]
Re^3: Request help on optimizing a loop for looking up numbers by Anonymous Monk on Dec 11, 2013 at 16:51 UTC
You can do something like `if (grep exists $hash{$_}, 7..12) {` but it's not necessarily any faster. A hash is an unordered data type, so there's no easy way to search for a range. (There are some "ordered hash" packages on cpan, but that's really a misleading name.)	[reply] [d/l]