Methods in php calls

PHP is one of the most popular web programming languages ​​currently, and it is widely used in the development of server-side web applications. In PHP, the method is to write a block of code for a specific function, which can be called repeatedly, thus avoiding the need to write similar code repeatedly. In this article, we will introduce methods in PHP calls, including defining methods, passing parameters, and calling methods.

1. Define methods

In PHP, you can use the function keyword to define methods, as shown below:

function 方法名() {
    代码块
}

The method name can be any legal one PHP identifier, the code block contains the specific function to be performed by the method. For example, the following example demonstrates how to define a simple method to output "Hello, World!":

function hello_world() {
    echo "Hello, World!";
}

2. Pass parameters

In actual programming, you may need to pass it to the method Some parameters so that the method can perform different tasks according to different needs. In PHP, parameters can be used in a method to extend its functionality, for example:

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

In the above example, the add() method receives two parameters: $a and $b, which are used to calculate their sum. and return the result. When calling the add() method, we need to pass two parameters, for example:

$first_num = 10;
$second_num = 20;
$result = add($first_num, $second_num);
echo $result; // 输出30

When calling the add() method, we pass the two parameters $first_num and $second_num, and assign their sum Give the $result variable and print it to the screen.

In addition to passing ordinary parameters, PHP also supports passing reference parameters. Reference parameters differ from ordinary parameters in that they allow methods to modify variables in the code that calls them. If you want to pass reference parameters, you can add an & symbol in front of the method parameters, for example:

function modify(&$str) {
    $str .= " is modified.";
}

In the above example, the modify() method receives a parameter $str, which is a string type variable, And added a "is modified." string at the end. Since reference parameters are passed, modifications within the method will also affect the code that calls it. For example:

$str = "this string";
modify($str);
echo $str; // 输出this string is modified.

In the above example, we first define a string type variable $str, and then pass it to the modify() method. Since the reference parameter is modified in the method, the value output outside the method is also modified.

3. Call the method

After defining the method, we can execute the code block by calling the method. When calling a method, you need to know the name of the method and the parameters that need to be passed to it, for example:

hello_world(); // 输出Hello, World!

In the above example, we called the method named hello_world(), which has no parameters and just outputs a Simple message.

If the method has a return value, it can be assigned to a variable, for example:

$result = add(10, 20);
echo $result; // 输出30

In the above example, we called the method named add() and passed two parameters 10 and 20, and assign its return value to the $result variable.

4. Summary

In PHP, method is a very important concept, which allows programmers to organize and reuse code more flexibly. When developing web applications, methods can be used to implement a variety of different functions, including data processing, input validation, page display, etc. This article introduces methods in PHP calls, including defining methods, passing parameters, and calling methods. If you need to write PHP code, it is very important to understand this knowledge.

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