How to use define modification function in php?

Usage of define modification function in php: 1. After setting, the value of the constant cannot be changed; 2. The constant name does not need the dollar sign [$] at the beginning; 3. The scope does not affect the use of the constant Access; 4. Constant values ​​can only be strings or numbers.

definemodify the use of function in php:

Definition and usage

#define()The function defines a constant.

Constants are similar to variables, the difference is:

• After setting, the value of the constant cannot be changed

• Constant The name does not need to start with a dollar sign ($)

• The scope does not affect access to constants

• The constant value can only be a string or Number

Syntax

define(name,value,case_insensitive)

##Example 1

Define a case-sensitive Constant:

<?php
define("GREETING","Hello world!");
echo constant("GREETING");
?>

Output:

Hello world!

Example 2

Define a case-insensitive constant:

<?php
define("GREETING","Hello world!",TRUE);
echo constant("greeting");
?>

Output:

Hello world!

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PHP programming from entry to proficiency

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