How to check whether a variable is null in PHP ?

We have given a variable and the task is to check whether the value of given variable is null or not and returns a Boolean value using PHP. To check a variable is null or not, we use is_null() function. A variable is considered to be NULL if it does not store any value. It returns TRUE if value of variable $var is NULL, otherwise, returns FALSE.

Syntax

boolean is_null( $var )

Example:

PHP

<?php
// PHP Program to check whether
// a variable is null or not?

$var1 = NULL;
$var2 = "\0"; // "\0" means null character
$var3 = "NULL";

// $var1 has NULL value, so always give TRUE
is_null($var1) ? print_r("True\n") : print_r("False\n");

// $var2 has '\0' value which consider as null in
// c and c++ but here taken as string, gives FALSE
is_null($var2) ? print_r("True\n") : print_r("False\n");

// $var3 has NULL string value so it will false
is_null($var3) ? print_r("True\n") : print_r("False\n");

?>

Output:

True
False
False