Associative array creation in PHP - Mini Project: Build & Apply

Associative Array Creation in PHP

📖 Scenario: You are creating a small contact list for your friends. Each friend has a name and a phone number.

🎯 Goal: Build an associative array in PHP that stores friends' names as keys and their phone numbers as values.

📋 What You'll Learn

Create an associative array called contacts with exact key-value pairs

Add a variable called new_contact set to 'Bob'

Use the array_key_exists function to check if a contact exists

Print the phone number of the new_contact if it exists

💡 Why This Matters

🌍 Real World

Associative arrays are used to store data with named keys, like contact lists, settings, or user profiles.

💼 Career

Knowing how to create and use associative arrays is essential for backend web development and data handling in PHP.

1

Create the contacts associative array

Create an associative array called contacts with these exact entries: 'Alice' => '123-4567', 'Bob' => '234-5678', and 'Charlie' => '345-6789'.

PHP

<?php

// Create the associative array 'contacts' with the given entries
// Your code here

Need a hint?

Use square brackets [] to create the array and separate key-value pairs with =>.

2

Add a new_contact variable

Add a variable called new_contact and set it to the string 'Bob'.

PHP

 '123-4567',
    'Bob' => '234-5678',
    'Charlie' => '345-6789'
];

// Add the variable 'new_contact' with value 'Bob'
// Your code here

Need a hint?

Use = to assign the string 'Bob' to the variable new_contact.

3

Check if new_contact exists in contacts

Use an if statement with array_key_exists to check if new_contact is a key in contacts. Inside the if, assign the phone number to a variable called phone_number.

PHP

 '123-4567',
    'Bob' => '234-5678',
    'Charlie' => '345-6789'
];

$new_contact = 'Bob';

// Use if and array_key_exists to check if 'new_contact' is in 'contacts'
// If yes, assign the phone number to 'phone_number'
// Your code here

Need a hint?

Use array_key_exists($new_contact, $contacts) inside the if condition.

4

Print the phone number

Print the value of phone_number using echo.

PHP

 '123-4567',
    'Bob' => '234-5678',
    'Charlie' => '345-6789'
];

$new_contact = 'Bob';

if (array_key_exists($new_contact, $contacts)) {
    $phone_number = $contacts[$new_contact];
}

// Print the phone number
// Your code here

Need a hint?

Use echo $phone_number; to display the phone number.