w3resource logo


PHP Tutorial

PHP : Constants

Secondary Nav

Description

A constant is an identifier for a simple value. The value cannot be modified during the script's execution. A valid constant name starts with a letter or underscore (no dollar($) sign before the name) and by convention constant identifier are always uppercase.

Constants are defined by using the define() function or by using the const keyword outside a class definition as of PHP 5.3.0. The name of the constant and the value must be placed within the parentheses. After defining it can never be changed or undefined. Only scalar data i.e. boolean, integer, float and string can be contained in constants.

PHP valid and invalid constant names

<?php
//Valid constants name
define("COUNTRY_NAME", "India");
define("CITYNAME", "New Delhi");
define("2NO_OF_STUDENTS", 60);
?>

Example of a PHP constant

<?php
define("COUNTRY_NAME", "India");
echo COUNTRY_NAME;
?>

Output :

India

View this example in browser



Join our Question Answer community to learn and share your programming knowledge.

Solve these problems:

Java: How to convert a string to an integer in Java?

C#: Loops in c#

SQL: JOIN using more than 5 tables