按哈希值排序到哈希数组的引用中

Question

我声明了以下数据：

#Content of "file.dat" 
#===========================
#Chaplin             Charlie             Basel               
#Estevez             Emilio              Santa Manica        
#Sarte               Jean Paul           Montmarte           
#Rikard              Frank               Amsterdam           
#Rodin               Paul                Montmarte           

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

my $file = "file.dat";
open NAMES_DAT, "file.dat" or die "Cannot open $file!\n";

print "\nInitial data.\n";
my @lines;
while ( my $line = <NAMES_DAT> ) {
    chomp($line);
    print $line . "\n";
    push(@lines, $line);
}
print "Num. reg: " . scalar(@lines) ."\n";

#We've been using an array of strings, now, we will transform
#this into an array of hashes, for direct access to each field.
my $account = {};
my $id = '';
foreach my $line (@lines) {
    my @record = split(' ', $line);
    my $set = {};
    $set = {    firstname  => $record[1],
        town       => $record[2],
           };
    $id = $record[0];   
    $account->{$id} = $set;
}

现在，我想对变量$ account进行排序，以获取由现场城镇订购的新帐户。 如何对此类数据使用函数排序？ 谢谢大家

Answer 1

$ account中没有顺序：它是对哈希的引用，并且哈希没有任何顺序。

您的意思是希望将城镇作为重点。 但是那些城镇后面应该是什么？ 假设我们要列出姓名和姓氏

一种方法是：

my $h ; 
for my $name (keys %{ $account}) {

    my $town = $account->{$name}{'town'} ;
    my $firstname = $account->{$name}{'firstname'} ;
    push @{ $h->{$town}{'firstnames'} }, $firstname ; 
    push @{ $h->{$town}{'names'} }, $name ;

}

这使 ：

$VAR1 = {
          'Basel' => {
                       'names' => [
                                    'Chaplin'
                                  ],
                       'firstnames' => [
                                         'Charlie'
                                       ]
                     },
          'Montmarte' => {
                           'names' => [
                                        'Rodin',
                                        'Sarte'
                                      ],
                           'firstnames' => [
                                             'Paul',
                                             'Jean-Paul'
                                           ]
                         },
          'Santa-Manica' => {
                              'names' => [
                                           'Estevez'
                                         ],
                              'firstnames' => [
                                                'Emilio'
                                              ]
                            },
          'Amsterdam' => {
                           'names' => [
                                        'Rikard'
                                      ],
                           'firstnames' => [
                                             'Frank'
                                           ]
                         }
        };