Abusing sort()

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Re: Abusing sort() by davidrw (Prior) on Jul 11, 2005 at 19:44 UTC
I think i see the basic idea, but i get this for output: `ckPartrao tunhlJe , eehsr` [download] Update: The above was on This is perl, v5.6.1 built for i386-linux ... I get the correct output on This is perl, v5.8.7 built for MSWin32-x86-multi-thread (activestate build 813). Update2: I changed the sort to be: `sort{$x=chop;print $x;(1+$x)*2-3}` and i get: `# v5.6.1: 110110010111100100001010000101100100110010000001010010110001 +11001001000100110100011 # v5.8: 1101100101111001000010100001011001001100100000010100101100011100100100 +0100110100011001110111101` [download] Note that the lengths are different, but they're identical up to that point. Anyone have an explaination?	[reply] [d/l] [select]
Re^2: Abusing sort() by jdalbec (Deacon) on Jul 12, 2005 at 01:42 UTC
`This is perl, v5.6.1 built for i386-linux ckPartrao tunhlJe , eehsr` [download] `This is perl, v5.8.1-RC3 built for darwin-thread-multi-2level Just another Perl hacker,` [download] `This is perl, v5.8.4 built for i386-linux-thread-multi Just another Perl hacker,` [download] Looks like Perl changed sort algorithms between 5.6 and 5.8. Try this on 5.6: `perl -e'$_=sprintf("%08b"x12,map hex,"194e8e91cc3a0097991c0350"=~/../g +);print sort{(1+chop)*2-3}split"","Puht r arJtel\ncerae on,khs";'` [download]	[reply] [d/l] [select]
Re: Abusing sort() by ysth (Canon) on Jul 12, 2005 at 00:36 UTC
This only works for me on perls >= 5.8.0.	[reply]
Re^2: Abusing sort() by phroggy (Monk) on Jul 12, 2005 at 01:39 UTC
Hmm, yeah, I'm seeing the same problem on perl 5.6.1; I had only tested this on 5.8.6. Apparently sort() works differently in 5.8. This works on 5.6.1: `perl -e'$_=sprintf("%08b"x12,map hex,"194E8E91CC3A0097991C0350"=~/../g);print sort{(1+chop)*2-3}split"","Puht r arJtel\ncerae on,khs";'`	[reply] [d/l]
Re^3: Abusing sort() by ysth (Canon) on Jul 12, 2005 at 01:44 UTC
See http://perldoc.perl.org/perl58delta.html#Performance-Enhancements. I think prior to that perl used its own quicksort algoritm (and prior to that, it used the libc quicksort, which could segfault on some platforms if the compare routine returned inconsistent info).	[reply]


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