sort hash

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Hi,

i need to sort hash in descending order.
but the issue is , in hash, i have key as integer value and the value associated with that key is string

so when i do sort it does not really sort the hash on the key level


i used follwoing code

foreach my $key (sort { $hash_fin{$b} <=> $hash_fin{$a} } keys %hash_fin) {
print "$key => $hash_fin{$key}\n";

}

the unsorted hash is :
12 => 20110622-035007-134
131 => 20110622-002139-131
107 => 20110621-215838-127
13 => 20110622-035007-134
129 => 20110621-235900-129
plz suggest
irfan
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Re: sort hash

On 23/06/2011 10:36, Irfan Sayed wrote:
> Hi,
>
> i need to sort hash in descending order.
> but the issue is , in hash, i have key as integer value and the value associated with that key is string
>
> so when i do sort it does not really sort the hash on the key level
>
>
> i used follwoing code
>
> foreach my $key (sort { $hash_fin{$b}<=> $hash_fin{$a} } keys %hash_fin) {
> print "$key => $hash_fin{$key}\n";
>
> }
>
> the unsorted hash is :
> 12 => 20110622-035007-134
> 131 => 20110622-002139-131
> 107 => 20110621-215838-127
> 13 => 20110622-035007-134
> 129 => 20110621-235900-129

It looks like you want to sort the hash elements by value?

For string data you must use the string comparator 'cmp' instead of the
numeric comparator. Take a look at the program below.

HTH,

Rob


use strict;
use warnings;

my %hash_fin = (
12 => '20110622-035007-134',
131 => '20110622-002139-131',
107 => '20110621-215838-127',
13 => '20110622-035007-134',
129 => '20110621-235900-129',
);

foreach my $key (sort { $hash_fin{$b} cmp $hash_fin{$a} } keys %hash_fin) {
printf "%-3d => '%s'\n", $key, $hash_fin{$key};
}

**OUTPUT**

13 => '20110622-035007-134'
12 => '20110622-035007-134'
131 => '20110622-002139-131'
129 => '20110621-235900-129'
107 => '20110621-215838-127'

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Re: sort hash

On 2011-06-23 11:36, Irfan Sayed wrote:

> [I need to sort a hash, but my keys are integers]

Realize that all hash keys are strings.


>sort { $hash_fin{$b} <=> $hash_fin{$a} } keys %hash_fin

You were almost there:

sort { $b <=> $a } keys %hash_fin

The <=> operator is numeric, so casts its operands to numeric.

--
Ruud

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Re: sort hash

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thanks rob. it worked ________________________________=0AFrom: R=
ob Dixon =0ATo: beginners@perl.org=0ACc: Irfan Sayed fan_sayed2002@yahoo.com>=0ASent: Thursday, June 23, 2011 3:37 PM=0ASubject:=
Re: sort hash On 23/06/2011 10:36, Irfan Sayed wrote:=0A> Hi,=0A> =0A=
> i need to sort hash in descending order.=0A> but the issue is , in hash, =
i have key as integer value and the value associated with that key is strin=
g=0A> =0A> so when i do sort it does not really sort the hash on the key le=
vel=0A> =0A> =0A> i used follwoing code=0A> =0A> foreach my $key (sort { $h=
ash_fin{$b}<=3D>=A0 $hash_fin{$a} } keys %hash_fin) {=0A> print "$key =3D>=
=A0 $hash_fin{$key}\n";=0A> =0A> }=0A> =0A> the unsorted hash is :=0A> 12 =
=3D>=A0 20110622-035007-134=0A> 131 =3D>=A0 20110622-002139-131=0A> 107 =3D=
>=A0 20110621-215838-127=0A> 13 =3D>=A0 20110622-035007-134=0A> 129 =3D>=A0=
20110621-235900-129 It looks like you want to sort the hash elements =
by value? For string data you must use the string comparator 'cmp' ins=
tead of the=0Anumeric comparator. Take a look at the program below. HT=
H, Rob =0Ause strict;=0Ause warnings; my %hash_fin =3D (=0A=
=A0 12=A0 =3D> '20110622-035007-134',   131 =3D> '20110622-002139-131',=
  107 =3D> '20110621-215838-127',   13=A0 =3D> '20110622-035007-13=
4',   129 =3D> '20110621-235900-129',=0A); foreach my $key (sort {=
$hash_fin{$b} cmp $hash_fin{$a} } keys %hash_fin) {   printf "%-3d =3D=
> '%s'\n", $key, $hash_fin{$key};=0A} **OUTPUT** 13=A0 =3D> '2011=
0622-035007-134'=0A12=A0 =3D> '20110622-035007-134'=0A131 =3D> '20110622-00=
2139-131'=0A129 =3D> '20110621-235900-129'=0A107 =3D> '20110621-215838-127'
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