state preserving uniq

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Re: state preserving uniq by xmath (Hermit) on Mar 01, 2003 at 10:54 UTC
Don't mean to be rude, but this can be done a lot simpler: `perl -ne '$s{lc $_}++ or print'` [download] (It's actually a standard example to which I added `lc`, and unlike your version it prints out the line right at its first occurrance, rather than first slurping in the whole file)	[reply] [d/l] [select]
Re^2: state preserving uniq by Aristotle (Chancellor) on Mar 01, 2003 at 17:28 UTC
Or even: `$s{+lc}++\|\|print` [download] `:-)` Makeshifts last the longest.	[reply] [d/l]
Re**3: state preserving uniq by xmath (Hermit) on Mar 01, 2003 at 17:39 UTC
Yea ofcourse; I was aiming for simplicity though, I wasn't golfing. :-) (it yields the same op-tree btw)	[reply]
Re: Re: state preserving uniq by Chady (Priest) on Mar 01, 2003 at 12:16 UTC
yea, but my code use a lot more memory than yours. ;) typical example on how NOT to code in perl. (I should get more sleep) nice one-liner He who asks will be a fool for five minutes, but he who doesn't ask will remain a fool for life. Chady \| http://chady.net/	[reply]
Re: Re: state preserving uniq by Anonymous Monk on Mar 01, 2003 at 15:58 UTC
And that can be sped up even more... `perl -ne 'print if 1 == ++$s{lc $_}'` [download] (The difference is that you don't have to create temporary variables.)	[reply] [d/l]
Re: Re: Re: state preserving uniq by xmath (Hermit) on Mar 01, 2003 at 16:22 UTC
Although I can't test it right now, I sincerely doubt that your version is faster, especially if you compare the optrees: Read more... (2 kB) While your version does save copying the old integer value to a temporary (you realize the temporary sv is allocated at compile-time, right?), it takes two extra ops, which I'm pretty sure costs more cpu time. And in any case the difference is too minimal (especially compared to lowercasing the string and doing a hash lookup) to justify adding to the code complexity	[reply] [d/l] [select]
Re: state preserving uniq by steves (Curate) on Mar 01, 2003 at 12:13 UTC
Why the lc? uniq as I know it is not case insensitive. You might want to note that behavior to any potential users.	[reply]
Re: state preserving uniq by Intrepid (Deacon) on Jul 30, 2003 at 19:02 UTC
This discussion also took place over here where a version is presented that takes its input on STDIN (like a typical *nix filter) as well as in the arguments in @ARGV.	[reply]


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