PHP, Structures and Functions, Fundamental Syntaxes

NULL

It's not the same as ZERO.

It's not the same as an EMPTY STRING.

It's not the same as a SPACE CHARACTER.

It is an abstraction of language.

Can be used to identify missing or unknown data

NULL is a type of variable commonly used in PHP.


<?php

/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

    A variable that has not yet been assigned value.
    
    A variable defined with the value of the NULL constant.
    
    A variable whose value was removed.

  - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

?>

In PHP, NULL can have one of the following assignments:

   * A variable that has not yet been assigned value.

   * A variable defined with the value of the NULL constant.

   * A variable whose value was removed.

In different languages, it can have different meanings.

In the next sections of this tutorial ...

... will be studied in more detail

See the exercise with examples of this type of variable:

EXERCISE



<?php

$varN01a = NULL;

$varN01b = null;

?>