This is_null() function is an inbuilt function in PHP which is used to find whether a variable is NULL or not. It returns True if the given variable is null, otherwise return False.
Syntax:
bool is_null( $var )
Example 1:
<?php // PHP program to illustrate // is_null() function // Declare variable and initialize it $x = NULL; $y = 15; // Use is_null() function and // display the result var_dump( is_null ( $x )); var_dump( is_null ( $y )); ?> |
bool(true) bool(false)
$x === null
It is an identical comparison operator and it returns true if the value of $x is equal to NULL. Null is a special data type in PHP which can have only one value that is NULL. A variable of data type NULL is a variable that has no value assigned to it. Any variable can be empty by setting the value NULL to the variable.
Syntax:
$var === null
Example:
<?php // PHP program to demonstrate // === operator // Declare variable and initialize it $x = "neveropen" ; if ( $x === null) echo "True \n" ; else echo "False \n" ; // Declare variable and initialize it $y = NULL; if ( $y === null) echo "True" ; else echo "False" ; ?> |
False True