Fetch every other item in a list

This is not obfuscation, but it might be useful and didn't quite fit anywhere else...
If you want to get every other item in a list or array, and don't care if the order is preserved, you can use this:

@a = keys   %{{@a}}    # for even indices
@a = values %{{@a}}    # for odd  indices
[download]

This is quite quick and powerful, but alas doesn't preserve the order.

Comment on Fetch every other item in a list Download Code

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RE: Fetch every other item in a list by japhy (Canon) on Oct 24, 2000 at 03:22 UTC
Also breaks on lists like ('foo', 'bar', 'foo', 'blat'). I'd suggest: `@even = @array[map 2$_, 0..$#array/2]; @odd = @array[map 2$_+1, 0..$#array/2];` [download] You can obfuscate this if you wish... `$_="goto+F.print+chop;\n=yhpaj";F1:eval`	[reply] [d/l]
RE: RE: Fetch every other item in a list by extremely (Priest) on Oct 24, 2000 at 05:16 UTC
Blew my last vote of the day on that post, japhy. =) I was coming back to post the basically same thing in an update to my post. -- $you = new YOU; honk() if $you->love(perl)	[reply]
RE (tilly) 1: Fetch every other item in a list by tilly (Archbishop) on Oct 24, 2000 at 05:20 UTC
Try the following for a strange version that you might find handy in obfuscation: `#! /usr/bin/perl (push @odd, $_)...(push @even, $_) foreach @ARGV; print map "$_\n", "Odd arguments:", (map " $_", @odd), "\nEven arguments:", (map " $_", @even);` [download] Be warned that you cannot construct a useful function this way though because it remembers state from function call to function call!	[reply] [d/l]
RE: Fetch every other item in a list by extremely (Priest) on Oct 24, 2000 at 03:33 UTC
Hmmm.. turn on "use strict;" and "-w" and try it with this array: `#!/usr/bin/perl -w use strict; my @list=("one", 1, "two", 2, 3, "Three", 3, "four", 5); print join("][", keys %{{@list}})."\n"; print join("][", values %{{@list}})."\n";` [download] This code is evil on odd sized lists, any list that may have duplicate "keys", and on the eyes. =) Good for "obfus" work where you know what your data is tho... -- $you = new YOU; honk() if $you->love(perl)	[reply] [d/l]