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|<- [[Booleans]]|[[Type juggling and casting]] ->|

===== NULL and empty =====

==== null ====

"NULL is a fancy term for nothing, for not having a value, it's not zero, not empty String, it's the actual lack of a value."

-> Permet d'assigner une variable à une absence de valeur.

<code>
$n = null; // or NULL, case-insensitive
$m = "hi";

echo is_null($n);
echo isset($n); // false
echo isset($m); // true
echo isset($o); // false (variable non déclarée).
</code>

==== empty ====

empty = "", null, 0, 0.0, "0", false, array().

<code>
echo empty(0);//true
echo empty(0.0);//true
echo empty("0");//true
echo empty(false);//true
echo empty(array());//true
echo empty(null);//true
echo empty("");//true
</code>

Attention à l'usage, si ces éléments sont une valeur acceptable. Empty & non null, empty & non numeric, etc.