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 = "GeeksforGeeks" ;
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
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