Master PHP Functions: Define, Pass, Loop, and Return Arrays

In PHP programming, arrays are a common and essential data type that can store multiple values as key‑value pairs, and they are frequently used inside custom functions.

1. Define an array

Use the array() function to create an array. Example: $my_array = array(1, 2, 3); Inside a function you can define an array in the same way:

function my_function() {
    $my_array = array(1, 2, 3);
}

2. Pass array as a parameter

When a function needs to operate on an array, pass the array as an argument:

function my_function($my_array) {
    // operate on $my_array
}

Call the function with an array variable.

3. Iterate over an array

Two common ways to traverse an array are a for loop and a foreach loop.

function my_function($my_array) {
    for ($i = 0; $i < count($my_array); $i++) {
        echo $my_array[$i] . "<br>";
    }
}

function my_function($my_array) {
    foreach ($my_array as $value) {
        echo $value . "<br>";
    }
}

4. Return an array

After processing, return the modified array to the caller:

return $my_array;

5. Full example

function my_function($my_array) {
    for ($i = 0; $i < count($my_array); $i++) {
        $my_array[$i] = $my_array[$i] * $my_array[$i];
    }
    return $my_array;
}
$my_input_array = array(1, 2, 3);
$my_output_array = my_function($my_input_array);
foreach ($my_output_array as $value) {
    echo $value . "<br>";
}

Summary

Defining, passing, iterating, and returning arrays in PHP functions are very common operations; choosing the appropriate loop (for or foreach) and correctly handling the array ensures efficient, reliable PHP applications.