PHP User-defined functions can perform specific tasks and be used repeatedly. Creating a custom function requires using a specific syntax to specify the function name and parameters. Example shows how to calculate the area of different shapes. Calling a custom function is similar to calling a built-in function. Managing custom functions includes registering, deleting, and viewing created functions.
Create and manage PHP user-defined functions
What are user-defined functions?
User-defined functions are blocks of code that you can create for yourself to perform specific tasks and reuse them as needed.
Create a custom function
To create a custom function, use the following syntax:
function function_name($parameter1, $parameter2, ...) { // 函数的代码 }
function_name
is the name of the function. parameter1
, parameter2
are optional parameters if you want the function to receive input. Example practice: Calculate area
Suppose you need to calculate the area of different shapes, you can use the following custom function:
function calcArea($shape, $parameters) { switch ($shape) { case "rectangle": return $parameters["length"] * $parameters["width"]; break; case "circle": return pi() * $parameters["radius"] ** 2; break; default: return "Invalid shape."; } } $rectArea = calcArea("rectangle", ["length" => 5, "width" => 3]); $circleArea = calcArea("circle", ["radius" => 2]); echo "Area of rectangle: $rectArea"; echo "<br>"; echo "Area of circle: $circleArea";
Calling a custom function
Calling a custom function is similar to calling a built-in function:
function_name($argument1, $argument2, ...);
argument1
, argument2
is the actual value passed to the function. Manage custom functions
register_shutdown_function()
function to register a custom function. unregister_shutdown_function()
function. get_defined_functions()
function you can get a list of all custom functions that have been created. The above is the detailed content of Creation and management of PHP user-defined functions. For more information, please follow other related articles on the PHP Chinese website!