Perl "Not an ARRAY reference"错误

Question

如果有人能启发我了解我的错误，我会很高兴:

my %mymap; 
@mymap{"balloon"} = {1,2,3};

print $mymap{"balloon"}[0] . "\n";

Answer 1

$mymap{'balloon'}是散列而不是数组。表达式 {1,2,3}创建一个哈希:

 {
   '1' => 2,
   '3' => undef
 }

您将其分配给 %mymap 的切片对应键列表:('balloon') .由于键列表是 1 项而值列表是一项，因此您执行了与

$mymap{'balloon'} = { 1 => 2, 3 => undef };

如果您使用过 strict和 warnings它会让你知道你的错误。我有:
Scalar value @mymap{"balloon"} better written as $mymap{"balloon"} at - line 3. Odd number of elements in anonymous hash at - line 3.