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PHP Functions: Understanding Basics
Defining a Function:
In PHP, functions are defined using the function keyword followed by the function name and parentheses. The code block within curly braces is the function body.
function sayHello() {
echo "Hello, World!";
}
sayHello();
Console Output:
Hello, World!
PHP Functions: Parameters and Arguments
Using Parameters:
Functions can take parameters, which are variables passed to the function. These are specified within the parentheses of the function definition.
function greet($name) {
echo "Hello, $name!";
}
greet("Alice");
Console Output:
Hello, Alice!
PHP Functions: Return Values
Returning Values:
Functions can return values using the return statement. This allows the function to send data back to the calling code.
function add($a, $b) {
return $a + $b;
}
$result = add(5, 3);
echo $result;
Console Output:
8
PHP Functions: Default Parameters
Default Parameter Values:
PHP allows you to set default values for function parameters. If no argument is provided, the default value will be used.
function greet($name = "Guest") {
echo "Hello, $name!";
}
greet();
Console Output:
Hello, Guest!
PHP Functions: Variable Scope
Understanding Scope:
Variables declared inside a function are local to that function and cannot be accessed outside. Global variables can be accessed using the global keyword.
$globalVar = "I am global";
function testScope() {
global $globalVar;
echo $globalVar;
}
testScope();
Console Output:
I am global
PHP Functions: Anonymous Functions
Anonymous Functions:
Anonymous functions, also known as closures, can be assigned to variables and passed as arguments to other functions.
$greet = function($name) {
echo "Hello, $name!";
};
$greet("Bob");
Console Output:
Hello, Bob!
PHP Functions: Recursive Functions
Recursive Functions:
A recursive function is a function that calls itself in order to solve a problem. It's commonly used for tasks that can be divided into similar subtasks.
function factorial($n) {
if ($n == 0) {
return 1;
} else {
return $n * factorial($n - 1);
}
}
echo factorial(5);
Console Output:
120
PHP Functions: Type Declarations
Type Declarations:
PHP 7 introduced type declarations, allowing you to specify the expected data types for function arguments and return values.
function sum(int $a, int $b): int {
return $a + $b;
}
echo sum(2, 3);
Console Output:
5
