Creation of PHP user-defined functions

PHP Custom functions allow encapsulation of code blocks, simplifying code and improving maintainability. Syntax: function function_name(argument1, argument2, ...) { // code block }. Create a function: function calculate_area($length, $width) { return $length * $width; }. Call the function: $area = calculate_area(5, 10);. Practical case: Use a custom function to calculate the total price of the items in the shopping cart, simplifying the code and improving readability.

Creation of PHP user-defined functions

In PHP, custom functions allow you to encapsulate a block of code into a reusable, maintainable unit . Custom functions can be used to perform specific tasks, simplifying your code and making your application more readable and maintainable.

Syntax

The syntax for creating a user-defined function is as follows:

function function_name(argument1, argument2, ...) {
    // 代码块
}

Where:

• function_name is the function name.
• argument1, argument2, etc. are optional parameters, representing the data passed to the function.
• // Code block Specifies the operation performed by the function.

Creating Functions

The following is an example of creating a custom function:

<?php
function calculate_area($length, $width) {
    return $length * $width;
}

This function calculates the area of ​​a rectangle between the given length and width.

Call a function

To call a custom function, simply use its name and pass any required parameters.

<?php
$area = calculate_area(5, 10);

Practical Case

The following example shows how to use a custom function to simplify the code for calculating the total price of the items in the shopping cart:

<?php
function calculate_total_price($items) {
    $total = 0;
    foreach ($items as $item) {
        $total += $item['price'] * $item['quantity'];
    }
    return $total;
}

$items = [
    ['price' => 10, 'quantity' => 2],
    ['price' => 15, 'quantity' => 3],
];

$total_price = calculate_total_price($items);

In the above example,calculate_total_price The function is used to calculate the total price of all items in an array. This function simplifies the total price calculation process, making it easier to read and maintain.

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