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Re: How to use a json string with nested array and nested hash elements?

by 7stud (Deacon)
on Feb 04, 2013 at 19:22 UTC ( #1016997=note: print w/replies, xml ) Need Help??

in reply to How to use a json string with nested array and nested hash elements?

#ref($docoded_json->{strarry} confirms array. Store in array for easi +er processing: my @jsonarray = $decoded_json->{strarray};

That's not how it works. Look at this code:

use strict; use warnings; use 5.012; use strict; use warnings; use 5.012; my @arr = ('a', 'b', 'c'); my %hash; $hash{letters} = \@arr; say ref $hash{letters}; --output:-- ARRAY

The output does not mean that $hash{letters} is an array. The output means that $hash{letters} is a *reference* to an array. In fact, ref() returns an empty string if its argument is not a reference, e.g. an array. So the very fact that ref returns a non-empty string for $hash{letters} means that $hash{letters} is some kind of reference; and the output "ARRAY" tells you what kind of *reference* it is.

So your ref output means that this line:

my @jsonarray = $decoded_json->{strarray};

is equivalent to writing this:

my @jsonarray = $aref;

And because the left of the assignment is 'list context', and because the right side is not a list, the right side gets promoted to a one element list, giving you this:

my @jsonarray = ($aref);

That succeeds in nesting your reference inside the array @jsonarray. To access the whole array referenced by $aref, you would have to write:

@{ $jsonarray[0] }

So originally when you found out that the right side of this assignment:

my @jsonarray = $decoded_json->{strarray};

produced ARRAY when you called ref() on it, that meant the right side was a reference to an array, and therefore to get the whole array you needed to dereference the right side:

my @jsonarray = @{ $decoded_json->{strarray} };

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