how to arrange array values in ascending order in perl - arrays

Question

I need to arrange the array values in ascending order in perl, i used sort compare option for below values but not working, kindly help as soon as possible
p1.txt
p10.txt
p11.txt
p12.txt
p13.txt
p14.txt
p15.txt
p16.txt
p17.txt
p18.txt
p19.txt
p2.txt
p20.txt
p21.txt
p22.txt
p23.txt
p24.txt
p3.txt
p4.txt
p5.txt
p6.txt
p7.txt
p8.txt
p9.txt
note: i want to sort the array values not array index
Thanks in advance

Answer 1

How about using schwartzian transform, doc here and here:
my #unsorted = qw(
p1.txt
p10.txt
p11.txt
p12.txt
p13.txt
p14.txt
p15.txt
p16.txt
p17.txt
p18.txt
p19.txt
p2.txt
p20.txt
p21.txt
p22.txt
p23.txt
p24.txt
p3.txt
p4.txt
p5.txt
p6.txt
p7.txt
p8.txt
p9.txt
);
my #sorted = map { $_->[0] }
sort { $a->[1] <=> $b->[1] }
map { (my $t=$_)=~s/\D+//g; [$_, $t] }
#unsorted;
dump#sorted;
output:
(
"p1.txt",
"p2.txt",
"p3.txt",
"p4.txt",
"p5.txt",
"p6.txt",
"p7.txt",
"p8.txt",
"p9.txt",
"p10.txt",
"p11.txt",
"p12.txt",
"p13.txt",
"p14.txt",
"p15.txt",
"p16.txt",
"p17.txt",
"p18.txt",
"p19.txt",
"p20.txt",
"p21.txt",
"p22.txt",
"p23.txt",
"p24.txt",
)

Answer 2

Consider using Sort::Naturally for this task:
use strict;
use warnings;
use Sort::Naturally qw/nsort/;
chomp( my #data = <DATA> );
print "$_\n" for nsort #data;
__DATA__
p1.txt
p10.txt
p11.txt
p12.txt
p13.txt
p14.txt
p15.txt
p16.txt
p17.txt
p18.txt
p19.txt
p2.txt
p20.txt
p21.txt
p22.txt
p23.txt
p24.txt
p3.txt
p4.txt
p5.txt
p6.txt
p7.txt
p8.txt
p9.txt
Partial output:
p1.txt
p2.txt
p3.txt
p4.txt
p5.txt
p6.txt
p7.txt
p8.txt
p9.txt
p10.txt
p11.txt
p12.txt
...
p22.txt
p23.txt
p24.txt
Hope this helps!

Answer 3

You need to create your own sort algorithm and pass that to sort:
sub custom_sort
{
$a =~ /^p(\d+)\.txt$/; #capture the number in $a
my $intA = $1;
$b =~ /^p(\d+)\.txt$/; #capture the number in $b
my $intB = $1;
return ($intA <=> $intB); #compare the numbers and return
}
And call:
#sortedArray = sort custom_sort #array;
See: http://perldoc.perl.org/functions/sort.html and http://perldoc.perl.org/perlop.html#Equality-Operators

Answer 4

Easiest would be to use the nsort_by function from List::UtilsBy; this sorts a list by the numbers returned from its code block. You would then invoke this with a code block to extract the number from the filename:
use List::UtilsBy qw( nsort_by );
my #sorted = nsort_by { /^p(\d+)\.txt$/ and $1 } #array;