我有一个Perl散列(来自一些遗留代码),但无法打印出键。Perl:引用键参数的类型必须是未散列的hashref或arrayref
if (ref $val eq ref {}) {
print "Keys: " . keys $val . "\n";
例如,这里的输出我得到:
VAL: HASH(0x7ff0898eda70)
Type of argument to keys on reference must be unblessed hashref or arrayref
我读过这Type of argument to keys on reference must be unblessed hashref or arrayref,但不知道如何在这种情况下应用它。
有没有办法解决这个问题?
====
UPDATE
我也试过:
print "Keys: " . keys %$val . "\n";
但仍获得Type of argument to keys on reference must be unblessed hashref or arrayref
更新2
我可以看到我有键a_key
但我无法打印出它的值。例如。与Carp::REPL
调试,我得到:
$ print $val;
1$ HASH(0x7fb1e0828f00)
$ print %$val;
1$ a_keyARRAY(0x7fb1e0828e28)
$ print %$val{'a_key'}
Compile error: syntax error at (eval 412) line 63, near "$val{"
BEGIN not safe after errors--compilation aborted at (eval 412) line 63, <FIN> line 6.
$ print $val{'a_key'}
Use of uninitialized value in print at (eval 413) line 63, <FIN> line 7.
1
更新3
在REPL我得到使用Data::Dumper
:
$ print Dumper($val);
$VAR1 = {
'a_key' => [
'long_value'
]
};
1$ print Dumper(%$val);
$VAR1 = 'a_key';
$VAR2 = [
'long_value'
];
1$ print %$val[1]
Compile error: syntax error at (eval 450) line 63, near "$val["
BEGIN not safe after errors--compilation aborted at (eval 450) line 63, <FIN> line 44.
$ print %$val{'a_key'}
Compile error: syntax error at (eval 451) line 63, near "$val{"
BEGIN not safe after errors--compilation aborted at (eval 451) line 63, <FIN> line 45.
$ print $val[1]
Use of uninitialized value in print at (eval 452) line 63, <FIN> line 46.
@ikegami你能详细点吗? – Snowcrash
我刚刚重新运行代码并得到相同的错误消息。 – Snowcrash
'.'设置标量上下文,但是当你修复这个'print'键时:“,键(%$ href),”\ n“;'你会将所有键连接成一个单词。您可以为键%$ href;执行'print“$ _”。打印“\ n”;',或每行一个'说键%$ href;' – zdim