Perl，dereference数组引用

Question

In the following Perl code, I would expect to be referencing an array reference inside an array 在下面的Perl代码中，我希望在数组中引用数组引用

#!/usr/bin/perl

use strict;
use warnings;

my @a=([1,2],[3,4]);

my @b = @$a[0];

print $b[0];

However it doesn't seem to work. 但它似乎不起作用。 I would expect it to output 1. 我希望它输出1。

@a is an array of references @a是一个引用数组

@b is $a[1] dereferenced (I think) @b是$a[1]解除引用（我认为）

So what's the problem? 所以有什么问题？

Answer 1

This stuff is tricky. 这个东西很棘手。

@$a[0] is parsed as (@$a)[0] , dereferencing the (undefined) scalar $a @$a[0]被解析为(@$a)[0] ，解除引用（undefined）标量$a

You wanted to say @{$a[0]} . 你想说@{$a[0]} 。