How to use PHP functions?

PHP Function Guide: Function Definition: Use function to declare function names and parameters. Call a function: Call a function using its name and parameters. Parameter passing: Use commas to separate multiple parameters. Return value: Use the return keyword to return the function result. Practical case: Calculate the circumference function circumference().

Guidelines for using PHP functions

A function is a block of code in PHP that performs a specific task and returns a result. Learning how to use functions effectively is crucial to writing efficient and maintainable PHP code.

Function syntax

The syntax of PHP function is as follows:

function function_name(parameter1, parameter2, ...) {
    // 函数体
}

• function_name is the name of the function.
• parameter1, parameter2, ... are the parameters passed to the function (optional).
• Function body is the code block of the task performed by the function.

Calling a function

You can call a function using the function name, followed by parentheses ():

$result = my_function($param1, $param2);

Passing parameters

The parameters are the data passed to the function. You can use commas to separate multiple parameters:

my_function('arg1', 'arg2', 3);

Return value

The function can return a value. Use the return keyword:

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

To get the return result of the function, assign it to a variable:

$sum = add(1, 2); // $sum 将等于 3

Practical case

Suppose we have A function that needs to calculate the circumference of a circle. We can create a function called circumference():

function circumference($radius) {
    return 2 * pi() * $radius;
}

Now we can use this function to calculate the circumference of a circle as follows:

$radius = 10;
$circumference = circumference($radius);

echo "圆的周长为: $circumference";

Output:

圆的周长为: 62.83185307179586

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