How do I compare two hashes in Perl without using Data::Compare?

Question

How do I compare two hashes in Perl without using Data::Compare?

Answer 1

The best approach differs according to your purposes. The FAQ item mentioned by Sinan is a good resource: How do I test whether two arrays or hashes are equal?. During development and debugging (and of course when writing unit tests) I have found Test::More to be useful when comparing arrays, hashes, and complex data structures. A simple example:

use strict;
use warnings;

my %some_data = (
    a => [1, 2, 'x'],
    b => { foo => 'bar', biz => 'buz' },
    j => '867-5309',
);

my %other_data = (
    a => [1, 2, 'x'],
    b => { foo => 'bar', biz => 'buz' },
    j => '867-5309x',
);

use Test::More tests => 1;
is_deeply(\%other_data, \%some_data, 'data structures should be the same');

Output:

1..1
not ok 1 - data structures should be the same
#   Failed test 'data structures should be the same'
#   at _x.pl line 19.
#     Structures begin differing at:
#          $got->{j} = '867-5309x'
#     $expected->{j} = '867-5309'
# Looks like you failed 1 test of 1.