Require and Include function in PHP; In this tutorial, you will learn learn require and include function of PHP with these function definitions, syntax, parameters, differences,s and examples.
When it comes to including files in PHP, two common methods are used: include() and require(). Both these functions are used to include other PHP files, but there are some differences between them that developers should understand.
The include() function is used to include a PHP file into another PHP file. If the file cannot be found or there is an error, a warning message is displayed, but the script will continue to run. The require() function works the same way as include(), but if the file cannot be found or there is an error, it will halt the script and display a fatal error.
So, when should you use include() and when should you use require()? The answer depends on how critical the included file is to the operation of your script. If the included file contains non-critical code, such as a header or footer, you should use include(). If the included file contains critical code, such as database connections or functions that are essential to the operation of your script, you should use require().
It is also important to note that the include() and require() functions have variants, such as include_once() and require_once(). These functions are used to include files only once, even if they are called multiple times in a script. This can help prevent issues with duplicate function or class definitions.
Include() and Require() Function in PHP
In PHP, Require and Include functions both are built-in functions of PHP. Both functions perform the same action.
- Include PHP Function
- Require PHP Function
- Example 1: How to use
include()andrequire()in PHP - Question 1:- What is the difference between include and require in PHP?
Include PHP Function
The include() function is used to include a file in a PHP script. This function includes the specified file and executes its code within the current script. If the specified file is not found, a warning message is displayed, but the script continues to execute.
Note:- The PHP include() function, it will produce a warning error, without halt the execution of PHP script.
Syntax:-
Here is the syntax for the include() function:
include 'path/filename.php';
Example of include() function
The example of PHP include() function is the following:
<html> <head> //include file using include() function <?php include 'path/head.php';?> </head> <body> <h1>include() function Example</h1> </body> </html>
Require PHP Function
The require() function is similar to the include() function in that it is used to include a file in a PHP script. However, there is one important difference between the two functions. If the specified file is not found, the require() function will produce a fatal error and stop the script from executing.
Note:- The PHP require() function, it will produce a fatal error and halt the execution of php script.
Syntax:-
Here is the syntax for the require() function:
require 'path/filename.php';
Example of Require() function
The example of PHP require() function is the following:
<html> <head> //require file using require() function <?php require 'path/head.php';?> </head> <body> <h1>include() function Example</h1> </body> </html>
Example 1: How to use include() and require() in PHP
Here is an example of how to use include() and require() in PHP:
// Using include() to include a non-critical file
include('header.php');
echo "Welcome to my website!";
include('footer.php');
// Using require() to include a critical file
require('database.php');
$db = new Database();
In the above example, header.php and footer.php are included using include(), since they contain non-critical code such as HTML markup. database.php, on the other hand, is included using require(), since it contains critical code such as the database connection.
Question 1:- What is the difference between include and require in PHP?
The main difference between include and require is how they handle errors when the specified file is not found. The include() function will continue to execute the script even if the file is not found, whereas the require() function will produce a fatal error and stop the script from executing.
When to use include
The include() function is useful when you want to include a file in a PHP script, but you don’t want the script to stop executing if the file is not found. For example, you may want to include a header or footer file in a PHP script, but if the file is not found, you can still display the content of the page.
When to use require
The require() function is useful when you want to include a file in a PHP script, but you want the script to stop executing if the file is not found. For example, you may want to include a configuration file in a PHP script, but if the file is not found, the script cannot run properly and should stop executing.
Conclusion
the include() and require() functions are both useful for including PHP files into other PHP files. The key difference between them is how they handle errors when the file cannot be found or there is an error in the included code. Developers should choose the appropriate function based on the criticality of the included file to their script’s operation.
And the difference between include and require in PHP comes down to how they handle errors when the specified file is not found. The include() function will continue to execute the script, while the require() function will produce a fatal error and stop the script from executing. Use include() when you want to include a file but don’t want the script to stop executing if the file is not found. Use require() when you want to include a file, but you want the script to stop executing if the file is not found.
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