grep is cool...

Post #197,482 by admin 3/7/05 12:08:15 PM Reply	grep is cool... My favorite is still $seen = ();\n@uniq = grep { !$seen{$_}++ } @stuff; This is somewhat nifty in Python 2.4, if you don't care about the order of the unique list: >>> stuff = (1,2,3,4,3,4,5,6,45,6,7,8,9,5,6)\n>>> print set(stuff)\n(1, 2, 3, 4, 5, 6, 7, 8, 9, 45) Regards, -scott anderson "Welcome to Rivendell, Mr. Anderson..."
Post #197,497 by FuManChu 3/7/05 1:02:55 PM Reply	Sure beats the old way >>> stuff = (1,2,3,4,3,4,5,6,45,6,7,8,9,5,6) >>> dict.fromkeys(stuff).keys() [1, 2, 3, 4, 5, 6, 7, 8, 9, 45] Sets are available in 2.3, by the way, just as a library module instead of a builtin. But you knew that. But not everyone does. ;)
Post #197,531 by ben_tilly 3/7/05 2:53:31 PM Reply	my %seen; # Not $seen = (); I assume that you want to be sure that %seen is an empty hash, not that the scalar $seen is set to be undef. Using strict catches this common typo. Cheers, Ben I have come to believe that idealism without discipline is a quick road to disaster, while discipline without idealism is pointless. -- Aaron Ward (my brother)
Post #197,537 by admin 3/7/05 4:22:17 PM Reply	shrug I got that from the Perl cookbook. And it does work, incidentally. Regards, -scott anderson "Welcome to Rivendell, Mr. Anderson..."
Post #197,538 by ben_tilly 3/7/05 4:28:56 PM Reply	Yes it does work. Once. Hashes start off empty. But if you put your code into a subroutine and call it twice, the second time around it will still be populated from the first. Incidentally I'm willing to bet, sight unseen, that the actual code in the cookbook got this right. :-P Cheers, Ben I have come to believe that idealism without discipline is a quick road to disaster, while discipline without idealism is pointless. -- Aaron Ward (my brother)
Post #197,539 by admin 3/7/05 4:38:02 PM Reply	Nope, you're right. I misread % as $; the cookbook has it correct. One more reason not to use Perl: it sucks for people with bad eyes. ;-) Regards, -scott anderson "Welcome to Rivendell, Mr. Anderson..."

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