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Date: Fri, 11 Jun 2010 20:04:03 +0200
Message-ID: <AANLkTimmNuGNwXowzatSwgEHyLsttEfSWbxguITxW2cs@mail.gmail.com>
To: Brian Moon <brian@moonspot.net>
Cc: PHP internals <internals@lists.php.net>
Content-Type: text/plain; charset=ISO-8859-1
Subject: Re: [PHP-DEV] Detecting if a null variable exists?
From: hannes.magnusson@gmail.com (Hannes Magnusson)

On Fri, Jun 11, 2010 at 19:43, Brian Moon <brian@moonspot.net> wrote:
> Is it just me or are we missing a way in the language to check if a variable
> that has been set to NULL exists or not?
>
> is_null() on an unset variable throws a NOTICE.
> $var === null throws a notice.
>
> So, you have to use isset()? But, ah,
>
> $var = null;
> if(isset($var))
>
> yields false.
>
> Is array_key_exists("var", $GLOBALS) the only solution to this problem?


This question creeps up every once in a while, and I have seen
bunchload of code that uses array_key_exists("foo", $array); rather
then isset($array["foo"]) because of it.

I however have never seen a proper usecase..
I tend to "initialize" my variables, and array keys, as null, so I
never have to do these kind of checks. And if you don't initialize
your variables, then you can turn of E_NOTICE if it bothers you.

-Hannes