{"id":920,"date":"2021-04-06T04:50:30","date_gmt":"2021-04-06T04:50:30","guid":{"rendered":"https:\/\/phptutorial.net\/?page_id=920"},"modified":"2025-04-06T07:51:36","modified_gmt":"2025-04-06T07:51:36","slug":"php-require","status":"publish","type":"page","link":"https:\/\/www.phptutorial.net\/php-tutorial\/php-require\/","title":{"rendered":"PHP require"},"content":{"rendered":"\n

Summary<\/strong>: in this tutorial, you will learn how to use the PHP require construct to load the code from a file into the current script.<\/p>\n\n\n\n

Introduction to PHP require construct #<\/a><\/h2>\n\n\n\n

PHP require<\/code> construct loads the code from a file into a script and executes that code. The following shows the syntax of the require<\/code> construct:<\/p>\n\n\n

<?php<\/span>\n\nrequire<\/span> 'path_to_file'<\/span>;<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
To load the code from a file, specify the file path after the require<\/code> keyword. When loading the file, the require<\/code> construct executes the code in the loaded file.<\/p>\n\n\n\n
The require<\/code> construct is the same as the include<\/code> construct except that if it fails to load the file, it’ll issue a fatal error and halt the script, whereas the include<\/code> construct only issues a warning and allows the script to continue.<\/p>\n\n\n\n
In practice, you often use the require<\/code> construct to load the code from libraries. Since the libraries contain the required functions to execute the script, it’s better to use the require<\/code> construct than the include<\/code> construct.<\/p>\n\n\n\n
PHP require example #<\/a><\/h2>\n\n\n\n
Suppose that you have index.php<\/code> and functions.php<\/code>, and you want to load the functions.php<\/code> to the index.php<\/code> file.<\/p>\n\n\n\n
The functions.php<\/code> file has one function called dd()<\/code>, which stands for the dump and die because it uses both var_dump()<\/code> and die()<\/code> functions:<\/p>\n\n\n
<?php<\/span>\n\nif<\/span> (!function_exists('d'<\/span>)) {\n\tfunction<\/span> dd<\/span>($data)<\/span>\n\t<\/span>{\n\t\techo<\/span> '<pre>'<\/span>;\n\t\tvar_dump($data);\n\t\techo<\/span> '<\/pre>'<\/span>;\n\t\tdie<\/span>();\n\t}\n}<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
The index.php will look like this:<\/p>\n\n\n
<?php<\/span>\n\nrequire<\/span> 'functions.php'<\/span>;\n\ndd([1<\/span>, 2<\/span>, 3<\/span>]);<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
In this file, we use the require<\/code> construct to load the code in functions.php<\/code> that defines the dd()<\/code> function if the function doesn’t exist. Then, we use dd()<\/code> function defined in the functions.php<\/code>.<\/p>\n\n\n\n
PHP require is not a function #<\/a><\/h2>\n\n\n\n
Sometimes, you see the following code:<\/p>\n\n\n
<?php<\/span>\n\nrequire<\/span>('functions.php'<\/span>);<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
The code looks like a function call because of the parentheses ()<\/code>. and it works.<\/p>\n\n\n\n
However, the parentheses are not a part of the require<\/code> construct. Instead, they belong to the file path expression that is being loaded.<\/p>\n\n\n\n
PHP require_once #<\/a><\/h2>\n\n\n\n
PHP require_once<\/code> is the counterpart of the include_once<\/code> except that the require_once issues an error if it fails to load the file. Also, the require_once<\/code> won’t load the file again if the file has been loaded.<\/p>\n\n\n\n
Here’s the syntax of the require_once construct:<\/p>\n\n\n
<?php<\/span>\n\nrequire_once<\/span> 'path_to_file'<\/span>;<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
Summary #<\/a><\/h2>\n\n\n\n
    \n
  • Use require<\/code> construct to load the code from another file into the script.<\/li>\n
  • Use require_once<\/code> construct to load the code from another file once and won’t include the file again if the file has been loaded.<\/li>\n
  • The require<\/code> and require_once<\/code> are language constructs, not functions.<\/li>\n<\/ul>\n
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