How do I determine the number of elements in an array reference?

Question

Here is the situation I am facing...

$perl_scalar = decode_json( encode ('utf8',$line));

decode_json returns a reference. I am sure this is an array. How do I find the size of $perl_scalar?? As per Perl documentation, arrays are referenced using @name. Is there a workaround?

This reference consist of an array of hashes. I would like to get the number of hashes.

If I do length($perl_scalar), I get some number which does not match the number of elements in array.

Answer 1

That would be:

scalar(@{$perl_scalar});

You can get more information from perlreftut.

You can copy your referenced array to a normal one like this:

my @array = @{$perl_scalar};

But before that you should check whether the $perl_scalar is really referencing an array, with ref:

if (ref($perl_scalar) eq "ARRAY") {
  my @array = @{$perl_scalar};
  # ...
}

The length method cannot be used to calculate length of arrays. It's for getting the length of the strings.

Answer 2

$num_of_hashes = @{$perl_scalar};

Since you're assigning to a scalar, the dereferenced array is evaluated in a scalar context to the number of elements.

If you need to force scalar context then do as KARASZI says and use the scalar function.