PHP is_null() Function

In PHP, the is_null() function is used to determine whether a variable is null or not. It returns a boolean value (true or false) depending on whether the variable is null.

Here’s the syntax of the is_null() function:

bool is_null ( mixed $variable )

Parameters:

• $variable: The variable that you want to check for null value.

Return Value:

• The function returns true if the $variable is null, and false otherwise.

Example:

<?php
$var1 = null;
$var2 = 10;

// Check if $var1 is null
if (is_null($var1)) {
    echo "\$var1 is null.\n";
} else {
    echo "\$var1 is not null.\n";
}

// Check if $var2 is null
if (is_null($var2)) {
    echo "\$var2 is null.\n";
} else {
    echo "\$var2 is not null.\n";
}
?>

Output:

$var1 is null.
$var2 is not null.

In the example above, we have two variables, $var1 and $var2. The first variable $var1 is explicitly set to null, while the second variable $var2 contains the value 10.

The is_null() function is used to check whether each variable is null or not. In the output, we can see that $var1 is null, and $var2 is not null.

The is_null() function is useful when you need to validate if a variable is set to null before performing certain operations. It helps to handle cases where a variable may or may not have a value assigned to it.