Array walk function in PHP - Mini Project: Build & Apply

Array walk function

📖 Scenario: You have a list of fruits with their prices. You want to increase each fruit's price by 10% to prepare for a sale.

🎯 Goal: Use the PHP array_walk function to update each fruit's price by increasing it by 10%.

📋 What You'll Learn

Create an associative array called fruits with exact keys and values

Create a function called increasePrice that increases the price by 10%

Use array_walk with increasePrice to update the prices

Print the updated fruits array

💡 Why This Matters

🌍 Real World

Increasing prices or applying discounts to product lists is common in online stores and inventory management.

💼 Career

Understanding how to manipulate arrays with functions like <code>array_walk</code> is useful for backend PHP developers working with data transformations.

1

Create the fruits array

Create an associative array called fruits with these exact entries: 'apple' => 100, 'banana' => 50, 'cherry' => 75.

PHP

<?php

// Create the fruits array with exact keys and values
// Your code here

Need a hint?

Use square brackets [] to create the array with keys and values.

2

Create the increasePrice function

Create a function called increasePrice that takes two parameters: &$price and $key. Inside the function, increase $price by 10% using $price *= 1.1;.

PHP

 100, 'banana' => 50, 'cherry' => 75];

// Create the increasePrice function below
// Your code here

Need a hint?

Remember to pass $price by reference using & so the original array updates.

3

Use array_walk to update prices

Use array_walk with the $fruits array and the increasePrice function to update each fruit's price.

PHP

 100, 'banana' => 50, 'cherry' => 75];

function increasePrice(&$price, $key) {
    $price *= 1.1;
}

// Use array_walk to apply increasePrice to $fruits
// Your code here

Need a hint?

Use the function name as a string in array_walk.

4

Print the updated fruits array

Print the $fruits array using print_r($fruits); to show the updated prices.

PHP

 100, 'banana' => 50, 'cherry' => 75];

function increasePrice(&$price, $key) {
    $price *= 1.1;
}

array_walk($fruits, 'increasePrice');

// Print the updated fruits array
// Your code here

Need a hint?

Use print_r to display the array in a readable format.