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)); ?> |
Output:
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"; ?> |
Output:
False True
