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

Hey monks,

I have an array that has negative numbers in it which I would like to sort ascending, but neither normal sort nor <=> sort seem to have an effect on the array positioning. I'm assuming this is because of the negative numbers involved. Anyone have a different <=> that would be able to sort negative numbers?

my @array = [ -15, 991, -9, 980, 1, 911, 281, 1299, 870, 1205, 1, 1 ]

Thanks!
Ineffectual

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Re: Negative number sorting?
by grep (Monsignor) on Dec 29, 2001 at 01:27 UTC
    Ineffectual
     [-15, 991, -9, 980, 1, 911, 281, 1299, 870, 1205, 1, 1]; is not array.
    It is array ref. Use () to signify an array. 
    #!/usr/bin/perl -w
use strict;
my @array = (-15,991, -9, 980, 1, 911, 281, 1299, 870, 1205, 1, 1);

my @new_array = sort { $a <=> $b } @array;

print "@new_array";

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    grep 
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Re: Negative number sorting?
by danger (Priest) on Dec 29, 2001 at 01:27 UTC

    Your array contains but a single element, and that element is an anymonous array (created with square brackets --- perhaps that is a typo when posting your code?). Use parentheses for ordinary list construction and remember that sort() does not sort in-place but instead returns the sorted list: 

    my @array = ( -15, 991, -9, 980, 1, 911, 281, 1299, 870, 1205, 1, 1 );
@array = sort { $a <=> $b } @array;
print "@array\n";
__END__

-15 -9 1 1 1 281 870 911 980 991 1205 1299

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[d/l]
      Ahh, I understand. My problem was with misunderstanding GD::Graph, not the sort. I was using square brackets because that made the GD::Graph module show up correctly, but the sort wouldn't work correctly. Now using "( )" and \@array, which causes it to show up correctly.

      Is there a way to remove duplicate values using sort or would I have to do a loop to remove them?

      Thanks.
      Ineffectual
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