is_null($x) vs $x === null in PHP

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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 = "zambiatek"; 
  
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"; 
      
?> 