Perl 无法将新的键/值对添加到匿名哈希中

Question

为了练习，我正在使用我找到的人为散列，并尝试添加新的键值对，但 perl 报告“编译错误：(F) 可能意味着您有语法错误” 哈希是

 my $selected = 'box';
 my $d = $design->{$selected};

my $design = {
    box => {
       ne => {data => 'north-east'},
       nw => {data => 'north-west'},
       n  => {data => 'north'},
       s  => {data => 'south'},
       e  => {data => 'east'},
       w  => {data => 'west'},
       se => {data => 'south-east'},
       sw => {data => 'south-west'},
    }
 };

为了添加一个新的键/值对，我已经尝试了所有我能想到的语法：

%{$design} = eastside=>ne;
$design{box}->{eastside}=Data=>ne;
%{$design}{box}={eastside=>Data=>ne};

这些都不起作用（以及这些的变体）。是不是因为它是一个复杂的哈希？

Answer 1

这里是您尝试添加到哈希的三行的重写，语法已更正。它可能不是您想要的确切代码，但它不应再引发错误。

#%{$design} = eastside=>ne;
$design{eastside} = 'ne';

#$design{box}->{eastside}=Data=>ne;
$design{box}{eastside} = {data => 'ne'};

#%{$design}{box}={eastside=>Data=>ne};
$design{box} = {eastside => {Data => 'ne'}};

我最初的想法可能是因为对 perl 生疏了： 看起来您开始使用的散列 $design 是 Dumper 的输出，而不是用于定义散列的实际 perl 语法。

尝试像这样定义哈希：

use Data::Dumper;
my %design
$design{'box'}{'ne'} = {'data' => 'north-east'};
$design{'box'}{'n'} = {'data' => 'north'};
$design{'box'}{'nw'} = {'data' => 'north-west'};

print $design{'box'}{'nw'}{'data'};
print "\n";
print Dumper(\%design);

应该输出：

north-west
$VAR1 = {
      'box' => {
                 'n' => {
                          'data' => 'north'
                        },
                 'ne' => {
                           'data' => 'north-east'
                         },
                 'nw' => {
                           'data' => 'north-west'
                         }
               }
    };