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PHP is_null() function

By using the is_null function, we can check whether the variable is NULL or not. This function was introduced in PHP 4.0.4.

SYNATX:

Parameter

Parameter	Description	Is compulsory
var	The variable being evaluated.	compulsory

Return Type:

The PHP is_null() function returns true if var is null, otherwise false.

Important Note:

We can unset the variable value by using the unset function.

Example 1

<?php
	$var1 = TRUE;
	if (is_null($var1))
		{
			echo 'Variable is  NULL';
		}
		else
		{
			echo 'Variable is not NULL';
		}
?>

Example 2

<?php
	$x= 100;
	unset($x);
	echo is_null($x);
?>

Example 3

<?php  
	$x = NULL; 
	$y = "\0";
	is_null($x) ? print_r("True\n") : print_r("False\n");
	echo "<br/>";
	is_null($y) ? print_r("True\n") : print_r("False\n");
?>

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