PHP, Mathematical Functions

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

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


<?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.



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



?>

EXERCISE




<?php



$varN01 = NULL;



$varN02 = null;



var_dump($varN01);



echo '<br><br>';



var_dump($varN02);



?>