Check if Variable is Null in PHP

In this tutorial we will learn How To Check if Variable is Null in PHP. PHP is_null() function is a built-in function which can be used to check whether a variable is null or not.

PHP is_null() Function

PHP is_null() Function is used to check if a variable is null or not.

is_null() function returns 1 if variable is null and 0 if it is not.

Variable is NULL if it has no value or if it has been assigned NULL.

<?php
$variable ='HowToCodeSchool.com';
if (is_null($variable))
{
echo "Variable is NULL";
}
else
{
echo "Variable is not NULL";
}
?>

In above code since variable has a string as it's value so it won't be called as NULL variable.

<?php
$variable = NULL;
if (is_null($variable))
{
echo "Variable is NULL";
}
else
{
echo "Variable is not NULL";
}
?>

While in second example, variable is a NULL variable.

<?php
if (is_null($variable))
{
echo "Variable is NULL";
}
else
{
echo "Variable is not NULL";
}
?>

In this third example, "Variable is NULL" will be printed since the variable we are checking doesn't exist.

Demo

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