Re^3: Sorting hash

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 <=>.

#!/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]

Comment on Re^3: Sorting hash Download Code

Replies are listed 'Best First'.
Re^4: Sorting hash by pryrt (Abbot) on Apr 05, 2018 at 19:30 UTC
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.	[reply] [d/l] [select]
Re^5: Sorting hash by ablanke (Monsignor) on Apr 05, 2018 at 22:56 UTC
Hi, you are right, but you get an warning: `Argument "0.04%" isn't numeric in numeric comparison (<=>)` the sorting order, in this trivial example, is the same, but who knows what shows up in the real world. so a numeric compare seems to be the more obvious choice in this case. of course there are several ways to get rid of the warnings and using numeric comparison.	[reply] [d/l]
Re^6: Sorting hash by pryrt (Abbot) on Apr 05, 2018 at 23:01 UTC
You're right. That'll remind me to turn on warnings even for oneliners...	[reply]


good chemistry is complicated, and a little bit messy -LW
	PerlMonks