THE WORLD'S LARGEST WEB DEVELOPER SITE

PHP Tutorial

PHP HOME PHP Intro PHP Install PHP Syntax PHP Comments PHP Variables PHP Echo / Print PHP Data Types PHP Strings PHP Numbers PHP Constants PHP Operators PHP If...Else...Elseif PHP Switch PHP While Loops PHP For Loops PHP Functions PHP Arrays PHP Sorting Arrays PHP Superglobals

PHP Forms

PHP Form Handling PHP Form Validation PHP Form Required PHP Form URL/E-mail PHP Form Complete

PHP Advanced

PHP Arrays Multi PHP Date and Time PHP Include PHP File Handling PHP File Open/Read PHP File Create/Write PHP File Upload PHP Cookies PHP Sessions PHP Filters PHP Filters Advanced

PHP OOP

PHP What is OOP PHP Classes/Objects PHP Constructor PHP Destructor PHP Access Modifiers PHP Inheritance PHP Constants PHP Abstract Classes PHP Traits PHP Static Methods PHP Static Properties

MySQL Database

MySQL Database MySQL Connect MySQL Create DB MySQL Create Table MySQL Insert Data MySQL Get Last ID MySQL Insert Multiple MySQL Prepared MySQL Select Data MySQL Delete Data MySQL Update Data MySQL Limit Data

PHP XML

PHP XML Parsers PHP SimpleXML Parser PHP SimpleXML - Get PHP XML Expat PHP XML DOM

PHP - AJAX

AJAX Intro AJAX PHP AJAX Database AJAX XML AJAX Live Search AJAX Poll

PHP Examples

PHP Examples PHP Quiz PHP Exercises PHP Certificate

PHP Reference

PHP Overview PHP Array PHP Calendar PHP Date PHP Directory PHP Error PHP Filesystem PHP Filter PHP FTP PHP JSON PHP Libxml PHP Mail PHP Math PHP Misc PHP MySQLi PHP Network PHP SimpleXML PHP Stream PHP String PHP XML Parser PHP Zip PHP Timezones

PHP is_nan() Function

❮ PHP Math Reference

Example

Check whether a value is 'not-a-number':

<?php
echo is_nan(200) . "<br>";
echo is_nan(acos(1.01));
?>
Try it Yourself »

Definition and Usage

The is_nan() function checks whether a value is 'not a number'.

This function returns true (1) if the specified value is 'not-a-number', otherwise it returns false/nothing.


Syntax

is_nan(value);

Parameter Values

Parameter Description
value Required. Specifies the value to check

Technical Details

Return Value: TRUE if value is 'not a number', FALSE otherwise
Return Type: Boolean
PHP Version: 4.2+

❮ PHP Math Reference