Sort function in Perl

Consider:

use warnings;

my @a = (1, 11, 3, 5, 21, 9, 10);

my @b = sort @a;

print "@b";

Output: 1 10 11 21 3 5 9

Codepad link: http://codepad.org/Fvhcf3eP

I guess t开发者_如何学编程he sort function is not taking the array's elements as an integer. That is why the output is not:

1 3 5 9 10 11 21

Is it?

How can I get the above result as output?

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The default implementation of Perl's sort function is to sort values as strings. To perform numerical sorting:

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

The linked page shows other examples of how to sort case-insensitively, in reverse order (descending), and so on.

You can create explicit subroutines to prevent duplication:

sub byord { $a <=> $b };
...
@a = sort byord @b;

This is functionally equivalent to the first example using an anonymous subroutine.

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You are correct. So just tell Perl to treat it as an integer like below.

File foop.pl

use warnings;

my @a = (1, 11, 3, 5, 21, 9, 10);

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

print "@b";

Run

perl foop.pl
1 3 5 9 10 11 21

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Provide a custom comparison function (comparing numerically):

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

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Here is a numerical sort:

@sorted = sort { $a <=> $b } @not_sorted   

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@b = sort { $a <=> $b } @a;

Is numerical

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Use the spaceship operator: sort { $a <=> $b } @a

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Guessing is the wrong approach. If you don't understand sort, look it up: sort

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