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Re: Numeric sorting WITHOUT <=>

by roboticus (Chancellor)
on Oct 10, 2012 at 02:52 UTC ( #998118=note: print w/ replies, xml ) Need Help??


in reply to Numeric sorting WITHOUT <=>

Just look at the definition of the <=> operator, and you should be able to code it up easily: $a <=> $b is negative when $a should precede $b, positive if $a should follow $b, and zero if $a and $b could be the same position. So if you're sorting numbers, you could just use $a - $b, as it returns appropriate values. Using $b - $a would sort in reverse:

$ cat ex_sort_odd.pl #!/usr/bin/perl use strict; use warnings; my @a; push @a, int(100*rand) for 1 .. 10; print "LIST: ", join(" ", @a), "\n"; my @b = sort { $a - $b } @a; print "ASC: ", join(" ", @b), "\n"; @b = sort { $b - $a } @a; print "DESC: ", join(" ", @b), "\n"; $ perl ex_sort_odd.pl LIST: 27 78 66 70 19 37 48 82 67 90 ASC: 19 27 37 48 66 67 70 78 82 90 DESC: 90 82 78 70 67 66 48 37 27 19

...roboticus

When your only tool is a hammer, all problems look like your thumb.


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