Re:Why programming is so much more than writing code

Well, I can't comment on the meaningfullness of the name as you've removed it, but the intent of the code is clear. Even if the formatting is a bit awkward. (operators at the end of the lines? Come on! This ain't Ruby ... you don't have to hint the compiler that we are not done with the statement yet!)

This, in my humble opinion, rather readable snippet of code is supposed to be used by the sort() routine and specifies that the AoA is to be sorted by 3rd, 2nd, 1st, 0th and 4th columns in this order of importance. You might want to use constants instead of the numbers to specify the columns, but that's about the best you can do.

Unless of course you want to factor out the indices and use something like

sub SUB_NAME {
 for (3,2,1,0,4) { # sort by the specified columns
  my $res = ($a->[$_] <=> $b->[$_]) and return $res;
 }
}
[download]

which would definitely need some explanation. Other than that whenever you see <=> or cmp, especially if comparing (some part of) $a and $b, think "sort".

Update: Oops. Good catch merlyn, thanks. A reminder to test the code I post here.

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Comment on Re:Why programming is so much more than writing code Download Code

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Re^2: Why programming is so much more than writing code by merlyn (Sage) on May 07, 2007 at 21:44 UTC
`my $res = ($a->[$_] <=> $b->[$_]) and return $res;` [download] Which doesn't work because $res isn't declared until after the end of the statement! Doh! Under `use strict`, this would fail, unless you happened to have another `$res` in scope, and then it'd be returning that, some of the time. Spooky. -- Randal L. Schwartz, Perl hacker	[reply] [d/l] [select]
Re^2: Why programming is so much more than writing code by GrandFather (Saint) on May 07, 2007 at 21:57 UTC
Update: Argh! see blazar's reply below Better would be: `sub SUB_NAME { # sort by the specified columns $_ = $a->[$_] <=> $b->[$_] and return $_ for 3, 2, 1, 0, 4; return 0; } }` [download] ;) DWIM is Perl's answer to Gödel	[reply] [d/l]
Re^3: Why programming is so much more than writing code by blazar (Canon) on May 07, 2007 at 22:05 UTC
Better would be: `sub SUB_NAME { # sort by the specified columns $_ = $a->[$_] <=> $b->[$_] and return $_ for 3, 2, 1, 0, 4; return 0; }` [download] `Modification of a read-only value attempted at 614055.pl line 3.`	[reply] [d/l] [select]