Let's take it a bit at a time, working out from the centre.

exec_select ($sql ) calls a function called "exec_select" passing it $sql.

We assume that this function returns an array reference, deference that reference and get the first element from the dereferenced array (that's @{ exec_select ($sql ) } [0]).

We then assume that the first element in that array contains a hash reference. We look for the "home1" key in the referenced array (that's @{ exec_select ($sql ) } [0] ->{ home1 }).

It's at this last stage that it goes wrong. We're assuming that we have a hash reference - but Perl finds undef instead. You (obviously) can't use undef as a hash reference so Perl throws an error.

You need to look at the value that is returned by exec_select. It is an array reference as expected, but the contents of that array (or, more specifically, the contents of the first element in that array) aren't what your code expects them to be.

--
<http://dave.org.uk>

"The first rule of Perl club is you do not talk about Perl club."
-- Chip Salzenberg

In reply to Re: Understanding this line of Code by davorg
in thread Understanding this line of Code by Anonymous Monk

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