Which types of PHP are case-insensitive?

#What are the case-insensitive functions in php?

php case-insensitive types:

1. Function names, method names, and class names are not case-sensitive
But it is recommended to use the same name as when defined

The code is as follows:

 <?php
 function show(){
 echo "Hello World";
 }

show(); //Output Hello World Recommended writing method

SHOW(); // The code to output Hello World

is as follows:

<?php
 class cls{
 static function func(){
 echo "hello world";
 }
 }
 Cls::FunC(); //输出hello world

2. Magic constants are not case-sensitive. It is recommended to use uppercase letters
including: __LINE__, __FILE__, __DIR__, __FUNCTION__, __CLASS__ , __METHOD__, __NAMESPACE__.

The code is as follows:

 <?php 
 echo __line__; //输出 2 
 echo __LINE__; //输出 3

3. NULL, TRUE and FALSE are not case sensitive

The code is as follows:

<?php
 $a = null;
 $b = NULL;
 $c = true;
 $d = TRUE;
 $e = false;
 $f = FALSE;
 var_dump($a == $b); //输出 boolean true
 var_dump($c == $d); //输出 boolean true
 var_dump($e == $f); //输出 boolean true

PHP Variable names are case-sensitive, but function names are not case-sensitive. This is a small detail that is often overlooked by novices. The test is as follows.

PHP function name is not case-sensitive test:

The code is as follows:

<?php
    function bbb(){
        echo &#39;abc&#39;;
    }
    function BBB(){
        echo "Abc";
    }
?>

Recommended tutorial: "PHP Video Tutorial"

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