PHP NULL (original) (raw)

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Summary: in this tutorial, you will learn about the PHP NULL type and how to check if a variable is null or not.

Introduction to the PHP null type #

The null is a special type in PHP. The null type has only one value which is also null. The null indicates the absence of a value for a variable.

A variable is null when you assign null to it like this:

`<?php

$email = null; var_dump($email); // NULL`Code language: PHP (php)

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In addition, when you use the unset() function to unset a variable, the variable is also null. For example:

`<?php

$email = '[email protected]'; unset($email);

var_dump($email); // NULL`Code language: PHP (php)

PHP NULL and case-sensitivity #

PHP keywords are case-insensitive. Therefore, NULL is also case-insensitive. It means that you can use null, Null, or NULL to represent the null value. For example:

`<?php

$email = null; $first_name = Null; $last_name = NULL;`Code language: PHP (php)

It’s a good practice to keep your code consistent. If you use null in the lowercase in one place, you should also use it in your whole codebase.

Testing for NULL #

To check if a variable is null or not, you use the is_null() function. The is_null() function returns true if a variable is null; otherwise, it returns false. For example:

`<?php

$email = null; var_dump(is_null($email)); // bool(true)

$home = 'phptutorial.net'; var_dump(is_null($home)); // bool(false)`Code language: PHP (php)

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To test if a variable is null or not, you can also use the identical operator ===. For example:

`<?php

$email = null; result=(result = (result=(email === null); var_dump($result); // bool(true)

$home= 'phptutorial.net'; result=(result = (result=(home === null); var_dump($result); // bool(false)`Code language: PHP (php)

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Summary #

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