Question

如何在不使用Data :: Compare的情况下比较Perl中的两个哈希值？

Answer 1

最佳方法根据您的目的而有所不同。 Sinan提到的FAQ项目是一个很好的资源：How do I test whether two arrays or hashes are equal?。在开发和调试期间（当然还有编写单元测试时），我发现Test::More在比较数组，散列和复杂数据结构时非常有用。一个简单的例子：

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');

输出：

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.

Answer 2

在谈论哈希时，比较不是一个足够详细的短语。有许多方法可以比较哈希：

他们有相同数量的钥匙吗？

if (%a == %b) {
    print "they have the same number of keys\n";
} else {
    print "they don't have the same number of keys\n";
}

两个哈希中的键是否相同？

if (%a != %b) {
    print "they don't have the same number of keys\n";
} else {
    my %cmp = map { $_ => 1 } keys %a;
    for my $key (keys %b) {
        last unless exists $cmp{$key};
        delete $cmp{$key};
    }
    if (%cmp) {
        print "they don't have the same keys\n";
    } else {
        print "they have the same keys\n";
    }
}

它们在两个哈希中是否具有相同的键和相同的值？

if (%a != %b) {
    print "they don't have the same number of keys\n";
} else {
    my %cmp = map { $_ => 1 } keys %a;
    for my $key (keys %b) {
        last unless exists $cmp{$key};
        last unless $a{$key} eq $b{$key};
        delete $cmp{$key};
    }
    if (%cmp) {
        print "they don't have the same keys or values\n";
    } else {
        print "they have the same keys or values\n";
    }
}

它们是同构的吗（我会把这个留给读者，因为我不想特别尝试从头开始实现它）？

或其他一些相等的衡量标准？

当然，这段代码只处理简单的哈希值。添加复杂的数据结构使其更加复杂。

Answer 3

请参阅How do I test whether two arrays or hashes are equal?

Perl的常见问题解答和答案是Perl发行版的一部分。您可以通过运行以下来查看perl附带的此答案的版本：

$ perldoc -q equal

在您的终端。

Answer 4

快速，肮脏，我确信效率不高：

use strict;
use warnings;

use Data::Dumper;

sub compare ($$) {
    local $Data::Dumper::Terse  = 1;
    local $Data::Dumper::Indent = 0;
    Dumper(shift) eq Dumper(shift);
}

my %a = ( foo => 'bar', bar => [ 0 .. 3 ] );
my %b = ( foo => 'bar', bar => [ 0 .. 3 ] );
my %c = ( foo => 'bar', bar => [ 0 .. 4 ] );

print Dumper compare \%a, \%b;
print Dumper compare \%a, \%c;

Answer 5

Test::Deep::NoTest具有相同的功能。

Answer 6

@zakovyrya看到这个答案：https://stackoverflow.com/a/2011443/2606517 键排序来自内部数据结构。

Answer 7

用于比较：

sub HashCompare {
  my ( $a, $b ) = @_;
  my %rhash_1 = %$a;
  my %rhash_2 = %$b;

  my $key         = undef;
  my $hash_2_line = undef;
  my $hash_1_line = undef;

  foreach $key ( keys(%rhash_2) ) {
   if ( exists( $rhash_1{$key} ) ) {
    if ( $rhash_1{$key} ne $rhash_2{$key} ) {
     print "key $key in $file_1 = $rhash_1{$key} & $rhash_2{$key} in $file_2\n";
         }
       }
     }
     else {
        print "key $key in  $file_1 is not present in $file_2\n";

            #next;
        }
    }

    foreach my $comp_key ( keys %rhash_1 ) {
        if ( !exists( $rhash_2{$comp_key} ) ) {
            print MYFILE "key $comp_key in  $file_2 is not present in $file_1\n";
        }
    }
    return;
}

创建没有重复键的哈希：

sub CreateHash {
    my (@key_val_file ) = @_;
    my $key_count      = 1;
    my %hash_key_val   = ();
    my $str4           = undef;

    local $/ = undef;

    foreach my $each_line (@key_val_file) {
            @key_val = split( /,/, $each_line );
            if ( exists( $hash_key_val{$key_val[0]} ) ) {
                    $key_count = $key_count + 1;
                    $str4      = $key_val[0] . " occurence-" . $key_count;
                    $hash_key_val{$str4} = $key_val[1];
                }
                else {
                    $hash_key_val{$key_name} = $key_val[1];
                }
            }
        }

        $key_count = 1;

    close FILE;

    return %hash_key_val;
}

如何在不使用Data :: Compare的情况下比较Perl中的两个哈希值？

7 个答案: