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Re: How does DBI return an arrayref with key/value pairs?

by grantm (Parson)
on Jun 24, 2013 at 01:59 UTC ( #1040346=note: print w/replies, xml ) Need Help??


in reply to How does DBI return an arrayref with key/value pairs?

I think you'll find the enlightenment you're after in perlreftut - Mark's very short tutorial about references.

When you called $rows = $dbh->selectall_arrayref, DBI returned a single scalar value which you assigned to $rows. That value was a reference to an array. Each element in that array was a reference to a hash of column names and values.

The array-dereferencing syntax you quoted:

$ { $array_ref } [2]

is exactly equivalent to this syntax:

$array_ref->[2]

And in your case would return a hashref.

my $hash_ref = $array_ref->[2]; my $value = $hashref->{$key};

You can also chain together the dereferencing like this:

my $value = $array_ref->[2]->{$key};

And you can even omit the arrow when the initial data structure contains references:

my $value = $array_ref->[2]{$key};

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