http://qs321.pair.com?node_id=1212366


in reply to Sorting hash

Hi,

since your Dump contains 2 'hostname' elements, i think you really have a ArrayRef which contains HashRefs.

you also have to take care of your sorting.

hopefully my example code helps:

#!/usr/bin/perl

use strict;
use warnings;
use Data::Dumper;

#Hash Number 1
my %hash1 = (
    'hostname' => {
        '1' => {
            'pass' => 1,
            'cpu' => '0.07%',
            'box_name' => 'hostname',
            'capacity' => '0.41%'
        }
    }
);

#Hash Number 2
my %hash2 = (
    'hostname' => {
        '1' => {
            'pass' => 1,
            'cpu' => '0.04%',
            'box_name' => 'hostname',
            'capacity' => '0.25%'
        }
    }
);

#Array of Hash Refs
my @array = ( \%hash1, \%hash2 );

#Array Ref
my $results = \@array;

#Result Elements (Hash Refs $a and $b) are dereferenced and values of 
+key cpu is used for sorting                                          
+      
foreach my $router ( sort { $a->{'hostname'}{1}{cpu} <=> $b->{'hostnam
+e'}{1}{cpu} } @{$results} ) {
    print Dumper($router);
}

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Re^2: Sorting hash
by bartrad (Beadle) on Apr 05, 2018 at 18:39 UTC

    Hi, thanks for the reply. Sorry, I redacted the data where hostname sat. Those values are in fact unique for each key.

    'hostname1' => {
                                                '1' => {
                                                         'pass' => 1,
                                                         'cpu' => '0.1
+1%',
                                                         'box_name' =>
+ '',
                                                         'capacity' =>
+ '0.57%'
                                                       }
                                              },
          'hostname2' => {
                                                   '1' => {
                                                            'pass' => 
+1,
                                                            'cpu' => '
+0.09%',
                                                            'box_name'
+ => '',
                                                            'capacity'
+ => '0.43%'
                                                          }
                                                 },

    [download]
[reply]
[d/l]

      Hi,

      there you go.

      i must confess that i missed also 1 thing in your sort function.

      the cpu percentage will not interpreted as an numeric value, so you have to use cmp instead of <=>.

      see perlop

      #!/usr/bin/perl

use strict;
use warnings;
use Data::Dumper;

my %results = (
    'hostname1' => {
        '1' => {
            'pass' => 1,
            'cpu' => '0.07%',
            'box_name' => 'hostname',
            'capacity' => '0.41%'
        }
    },
    'hostname2' => {
        '1' => {
            'pass' => 1,
            'cpu' => '0.04%',
            'box_name' => 'hostname',
            'capacity' => '0.25%'
        }
    }
);

my $results = \%results;
                                                
foreach my $router ( sort { $results->{$a}{1}{cpu} cmp $results->{$b}{
+1}{cpu} } keys %{results} ) {
    print Dumper($results->{$router});
}

      [download]
[reply]
[d/l]
        the cpu percentage will not interpreted as an numeric value

        Actually, due to Perl trying to numberify a string in numeric context, it turns out percents written as strings get reasonably interpreted as numbers: 

        C:\WINDOWS\system32>perl -MDevel::Peek=Dump -le " $a = qq(3.14%); Dump
+ $a; $b = qq(2.718%); Dump $b; print $a <=> $b; Dump $a; Dump $b"
SV = PV(0x1daf58) at 0x44d2660
  REFCNT = 1
  FLAGS = (POK,IsCOW,pPOK)
  PV = 0x44ebf28 "3.14%"\0
  CUR = 5
  LEN = 10
  COW_REFCNT = 1
SV = PV(0x1dafb8) at 0x44d2300
  REFCNT = 1
  FLAGS = (POK,IsCOW,pPOK)
  PV = 0x44ebe68 "2.718%"\0
  CUR = 6
  LEN = 10
  COW_REFCNT = 1
1
SV = PVNV(0x1d9288) at 0x44d2660
  REFCNT = 1
  FLAGS = (POK,IsCOW,pNOK,pPOK)
  IV = 0
  NV = 3.14
  PV = 0x44ebf28 "3.14%"\0
  CUR = 5
  LEN = 10
  COW_REFCNT = 1
SV = PVNV(0x1d9268) at 0x44d2300
  REFCNT = 1
  FLAGS = (POK,IsCOW,pIOK,pNOK,pPOK)
  IV = 2
  NV = 2.718
  PV = 0x44ebe68 "2.718%"\0
  CUR = 6
  LEN = 10
  COW_REFCNT = 1

        [download]
        ... They start out as just the string (PV); but after running numeric compare, you can see that it had the right output value for $a <=> $b (1) and afterward, they also have the reasonable floating-point value (NV) of 3.14 and 2.718.

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