PHP is_null() Function

Syntax

is_null(variable);

Parameter	Description
Variable	Any variable (Required)

<?php

$a = " NULL ";
if(is_null($a))
{
echo " Null ";	
}
else
{
echo " Not null ";
}

?>

Not null

In above example $a is a variable and NULL is a string so that result will be not null. Double or single quotes represent the string.

It returns TRUE if the variable is NULL otherwise return false.

Is_null() function is used to check the variable is empty or not.

An undeclared $variable will return TRUE but may return an error.

<?php

$a="";

var_dump(is_null($a));

?>

In above example $a is a variable but not null so that result will be false.

<?php

$number = NULL;

var_dump(is_null($number));

$number1 = " John " ;

var_dump(is_null($number1));

?>

$number is a variable and NULL is not a string, its represent the variable with no value. SO result will be true.

$number is a string variable that hold some value so that result will be false.