How to create a PHP library and load it?

How to create a PHP function library and load it? Create a function library file containing the functions to be defined. Use include or require statements to load a function library file to make its functions available to the current script.

How to create a PHP function library and load it

Create a function library

First, we need to create a file to hold our function library. For the purposes of this tutorial, we will create a file called my_functions.php:

<?php

function greet($name) {
  echo "Hello $name!\n";
}

function add($a, $b) {
  return $a + $b;
}

This file contains two functions: greet() and add().

Load function library

Next, we need to load the function library file so that we can use the functions in it. There are two ways to do this:

Method 1: Using the include

include statement will specify The contents of the file are inserted into the current script. To load the function library, we can use the following syntax:

include 'my_functions.php';

Method 2: Use the require

require statement with include Similar, but it generates a fatal error if the specified file does not exist or cannot be read. The syntax is as follows:

require 'my_functions.php';

Practical case

Once the function library is loaded, we can use the functions in it. Let’s see an example of greeting the user using the greet() function:

<?php

include 'my_functions.php';

$name = 'John';
greet($name); // 输出：Hello John!

We can also use the add() function to calculate the sum of two numbers:

<?php

include 'my_functions.php';

$num1 = 5;
$num2 = 10;
$sum = add($num1, $num2); // $sum 现在等于 15

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