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Re: Sorting a File which contains numbers

by valavanp (Curate)
on Oct 30, 2006 at 13:24 UTC ( #581282=note: print w/replies, xml ) Need Help??


in reply to Sorting a File which contains numbers

You can try this: 
use strict;
use warnings;

my @a=(1,5,2,4);
print "Ascending order:";
print sort(@a);
print "\n";
print "Descending order:";
print reverse sort(@a);

[download]

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Re^2: Sorting a File which contains numbers
by johngg (Canon) on Oct 30, 2006 at 14:50 UTC
    Your solution is going to fail as soon as you encounter numbers that are more than single-digits because the default sort that you use is lexical, not numeric. Consider

    perl -le '@arr = (2, 17, 8, 5, 26);
print for sort @arr;'

    [download]

    produces

    17
2
26
5
8

    [download]

    whereas

    perl -le '@arr = (2, 17, 8, 5, 26);
print for sort {$a <=> $b} @arr;'

    [download]

    does a numerical sort and produces

    2
5
8
17
26

    [download]

    To sort descending numerically change the anonymous sort routine to {$b <=> $a} rather than using reverse.

    Cheers,

    JohnGG

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