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How do I refer to an element of a hash of arrays as an array

( #62964=categorized question: print w/ replies, xml ) Need Help??
Contributed by Anonymous Monk on Mar 08, 2001 at 19:11 UTC
Q&A  > references


Description:

I create a hash where each element refers to an array:

$h{'one'} = [1,2,3];
I can access the individual array elements o.k.:
print "$h{'one'}[1]\n";
prints "2" as I expect.

Why can't I access the entire array as if it were a regular array?
What don't I understand here:

my @a = $h{'one'}; print "$a[1]\n";
doesn't do what I expect.

Answer: How do I refer to an element of a hash of arrays as an array
contributed by arturo

Since hash values can only be scalars, the value is a reference to an array. That is, it's like a pointer. (Try print "$h{'one'}\n" and see what you get.)

To get at the thing the reference points to, you need to explicitly dereference it. To get at the array, do

my @a = @{ $h{one} };
By enclosing something in the @{ } construction, you're saying that you want the array to which that reference points.

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