Perl Golf-- testing array intersection

BUU has asked for the wisdom of the Perl Monks concerning the following question:

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Re: Perl Golf-- testing array intersection by GrandFather (Saint) on Jan 30, 2006 at 21:26 UTC
Not only does it return an incorrect result, it contains a gratuitous space. Prepending "scalar " to the code fixes the result and with the extra space removed gives a 34 stroke solution. There is a 29 stroke solution that gives the correct result. DWIM is Perl's answer to Gödel	[reply]
Re^2: Perl Golf-- testing array intersection by Aristotle (Chancellor) on Jan 30, 2006 at 21:36 UTC
Prepending `0+` also fixes the context issue but is 4 characters shorter than “scalar”. Makeshifts last the longest.	[reply] [d/l]
Re^3: Perl Golf-- testing array intersection by GrandFather (Saint) on Jan 30, 2006 at 21:40 UTC
Spoiler :) Actually 5 strokes shorter because scalar requires a space after it before the grep. DWIM is Perl's answer to Gödel	[reply]
Re: Perl Golf-- testing array intersection by Errto (Vicar) on Jan 30, 2006 at 21:21 UTC
27 unless I'm making some mistake: `sub match { # 123456789012345678901234567 ++$c{$_}for@x;grep$c{$_},@y }` [download] Note that this assumes the sub will be called in scalar context	[reply] [d/l]
Re: Perl Golf-- testing array intersection by Aristotle (Chancellor) on Jan 30, 2006 at 21:30 UTC
Both your and Errto’s solutions violate your spec: they will ignore duplicate elements in `@x`, but they report duplicate matches in `@y`. The best I’ve come up with that works correctly is 49 characters (or 51 if you care about the context issue). <Reveal this spoiler or all in this thread> Makeshifts last the longest.	[reply] [d/l]
Re^2: Perl Golf-- testing array intersection by Errto (Vicar) on Jan 30, 2006 at 22:17 UTC
My interpretation of the spec allowed that behavior but ok, here's one at 45 chars that follows the duplicate rule: <Reveal this spoiler or all in this thread>	[reply] [d/l]
Re^3: Perl Golf-- testing array intersection by Aristotle (Chancellor) on Jan 30, 2006 at 22:43 UTC
Nice! I bid 38. `sub match { # 1 2 3 # 12345678901234567890123456789012345678 $_++for@c{@x},@d{@y};grep$d{$_},keys%c }` [download] Makeshifts last the longest.	[reply] [d/l]
Re: Perl Golf-- testing array intersection by GrandFather (Saint) on Jan 30, 2006 at 22:37 UTC
47 strokes with scalar returned and 45 strokes with list returned. <Reveal this spoiler or all in this thread> DWIM is Perl's answer to Gödel	[reply] [d/l]
Re: Perl Golf-- testing array intersection by martin (Friar) on Jan 31, 2006 at 02:42 UTC
thundergnat relies on @x neither having `'0'` nor `''` elements. I think I can do better: 33 in scalar context, else 35: <Reveal this spoiler or all in this thread>	[reply] [d/l]
Re: Perl Golf-- testing array intersection by samtregar (Abbot) on Jan 30, 2006 at 21:16 UTC
Your sub returns a list of 1s, which doesn't seem correct to me. -sam	[reply]
Re^2: Perl Golf-- testing array intersection by Aristotle (Chancellor) on Jan 30, 2006 at 21:22 UTC
In scalar context, it does return the number of 1s, which is what he wants. Makeshifts last the longest.	[reply]
Re: Perl Golf-- testing array intersection by thundergnat (Deacon) on Jan 31, 2006 at 01:00 UTC
Hmmm.... 25 if you can't have duplicate values in the second array. 39 if you can. (if it is allowed to return a list, 23 and 37. Remove 0+ from each.) <Reveal this spoiler or all in this thread>	[reply] [d/l] [select]