Applying Associative Arrays to Real-World Challenges in PHP

Introduction and Goal Setting

Hello there! In this lesson, we will apply associative arrays to real-world challenges using PHP . Our focus will be on solving tasks such as cataloging books in a library, counting votes in an election, and tracking inventories.

Real-World Scenarios Calling for Associative Arrays

Associative arrays in PHP are beneficial in real-life applications, such as the ones mentioned above, due to their ability to rapidly retrieve data using unique keys and efficiently handle larger datasets. Let's understand their efficiency with some practical examples.

Solving Real-World Task 1: Cataloging Books in a Library

Suppose you're asked to manage the cataloging of books in a library. Here, the book ID serves as the key, while the details of the book, such as the title, author, and year of publication, are stored as values. This approach allows us to add, search for, and remove books from our library catalog using just a few lines of PHP code. <?php // Initializing an associative array $libraryCatalog = []; // Details of a book $bookId = "123"; // Creating an associative array to store details of the book $bookDetails = [ "title" => "To Kill a Mockingbird", "author" => "Harper Lee", "year_published" => "1960" ]; $libraryCatalog[$bookId] = $bookDetails; // Adding a book to library catalog, where value itself is an associative array // Searching for a book if (array_key_exists($bookId, $libraryCatalog)) { echo "Title: " . $libraryCatalog[$bookId]["title"] . ", Author: " . $libraryCatalog[$bookId]["author"] . ", Year Published: " . $libraryCatalog[$bookId]["year_published"] . "\n"; } unset($libraryCatalog[$bookId]); // Removing a book from the library ?> As you can see, associative arrays make the task of cataloging books in the library simpler and more efficient!

Solving Real-World Task 2: Counting Votes in an Election

Imagine a scenario in which we need to count votes in an election. We employ an associative array, where each name is a unique key, and the frequency of that name serves as the associated value. Let's write some PHP code to better understand this. <?php $votesList = ["Alice", "Bob", "Alice", "Charlie", "Bob", "Alice"]; // Cast votes $voteCounts = []; // Initializing an associative array // Counting the votes foreach ($votesList as $name) { if (!array_key_exists($name, $voteCounts)) { $voteCounts[$name] = 0; } $voteCounts[$name]++; } foreach ($voteCounts as $name => $count) { echo $name . ": " . $count . "\n"; } // Prints: Alice: 3, Bob: 2, Charlie: 1 ?> Associative arrays facilitate the efficient counting of votes.

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PHP

<?php
// Initializing an associative array
$libraryCatalog = [];

// Details of a book
$bookId = "123";
// Creating an associative array to store details of the book
$bookDetails = [
    "title" => "To Kill a Mockingbird",
    "author" => "Harper Lee",
    "year_published" => "1960"
];

$libraryCatalog[$bookId] = $bookDetails;  // Adding a book to library catalog, where value itself is an associative array

// Searching for a book
if (array_key_exists($bookId, $libraryCatalog)) {
    echo "Title: " . $libraryCatalog[$bookId]["title"] . 
         ", Author: " . $libraryCatalog[$bookId]["author"] . 
         ", Year Published: " . $libraryCatalog[$bookId]["year_published"] . "\n";
}

unset($libraryCatalog[$bookId]);  // Removing a book from the library
?>

<?php
// Initializing an associative array
$libraryCatalog = [];

// Details of a book
$bookId = "123";
// Creating an associative array to store details of the book
$bookDetails = [
    "title" => "To Kill a Mockingbird",
    "author" => "Harper Lee",
    "year_published" => "1960"
];

$libraryCatalog[$bookId] = $bookDetails;  // Adding a book to library catalog, where value itself is an associative array

// Searching for a book
if (array_key_exists($bookId, $libraryCatalog)) {
    echo "Title: " . $libraryCatalog[$bookId]["title"] . 
         ", Author: " . $libraryCatalog[$bookId]["author"] . 
         ", Year Published: " . $libraryCatalog[$bookId]["year_published"] . "\n";
}

unset($libraryCatalog[$bookId]);  // Removing a book from the library
?>

PHP

<?php
$votesList = ["Alice", "Bob", "Alice", "Charlie", "Bob", "Alice"];  // Cast votes
$voteCounts = [];  // Initializing an associative array

// Counting the votes
foreach ($votesList as $name) {
    if (!array_key_exists($name, $voteCounts)) {
        $voteCounts[$name] = 0;
    }
    $voteCounts[$name]++;
}

foreach ($voteCounts as $name => $count) {
    echo $name . ": " . $count . "\n";
}
// Prints: Alice: 3, Bob: 2, Charlie: 1
?>

<?php
$votesList = ["Alice", "Bob", "Alice", "Charlie", "Bob", "Alice"];  // Cast votes
$voteCounts = [];  // Initializing an associative array

// Counting the votes
foreach ($votesList as $name) {
    if (!array_key_exists($name, $voteCounts)) {
        $voteCounts[$name] = 0;
    }
    $voteCounts[$name]++;
}

foreach ($voteCounts as $name => $count) {
    echo $name . ": " . $count . "\n";
}
// Prints: Alice: 3, Bob: 2, Charlie: 1
?>

PHP

<?php
$storeInventory = [];
$storeInventory["Apples"] = 100;
$storeInventory["Bananas"] = 80;
$storeInventory["Oranges"] = 90;  // Initializing an inventory

$storeInventory["Pears"] = 50;  // Adding a new product to inventory and setting its quantity

$storeInventory["Apples"] += 20;  // Updating the number of apples in inventory

$prod = "Apples";  // A product to be checked
echo "Total " . $prod . " in stock: " . $storeInventory[$prod] . "\n";

// Check if a product is in stock
$prod = "Mangoes";
if (array_key_exists($prod, $storeInventory)) {  // If mangoes exist in inventory
    echo $prod . " are in stock.\n";
} else {  // If mangoes don't exist in inventory
    echo $prod . " are out of stock.\n";
}
?>

<?php
$storeInventory = [];
$storeInventory["Apples"] = 100;
$storeInventory["Bananas"] = 80;
$storeInventory["Oranges"] = 90;  // Initializing an inventory

$storeInventory["Pears"] = 50;  // Adding a new product to inventory and setting its quantity

$storeInventory["Apples"] += 20;  // Updating the number of apples in inventory

$prod = "Apples";  // A product to be checked
echo "Total " . $prod . " in stock: " . $storeInventory[$prod] . "\n";

// Check if a product is in stock
$prod = "Mangoes";
if (array_key_exists($prod, $storeInventory)) {  // If mangoes exist in inventory
    echo $prod . " are in stock.\n";
} else {  // If mangoes don't exist in inventory
    echo $prod . " are out of stock.\n";
}
?>

PHP

<?php
// Initializing an associative array
$libraryCatalog = [];

// Details of a book
$bookId = "123";
// Creating an associative array to store details of the book
$bookDetails = [
    "title" => "To Kill a Mockingbird",
    "author" => "Harper Lee",
    "year_published" => "1960"
];

$libraryCatalog[$bookId] = $bookDetails;  // Adding a book to library catalog, where value itself is an associative array

// Searching for a book
if (array_key_exists($bookId, $libraryCatalog)) {
    echo "Title: " . $libraryCatalog[$bookId]["title"] . 
         ", Author: " . $libraryCatalog[$bookId]["author"] . 
         ", Year Published: " . $libraryCatalog[$bookId]["year_published"] . "\n";
}

unset($libraryCatalog[$bookId]);  // Removing a book from the library
?>

PHP

<?php
$votesList = ["Alice", "Bob", "Alice", "Charlie", "Bob", "Alice"];  // Cast votes
$voteCounts = [];  // Initializing an associative array

// Counting the votes
foreach ($votesList as $name) {
    if (!array_key_exists($name, $voteCounts)) {
        $voteCounts[$name] = 0;
    }
    $voteCounts[$name]++;
}

foreach ($voteCounts as $name => $count) {
    echo $name . ": " . $count . "\n";
}
// Prints: Alice: 3, Bob: 2, Charlie: 1
?>

PHP

<?php
$storeInventory = [];
$storeInventory["Apples"] = 100;
$storeInventory["Bananas"] = 80;
$storeInventory["Oranges"] = 90;  // Initializing an inventory

$storeInventory["Pears"] = 50;  // Adding a new product to inventory and setting its quantity

$storeInventory["Apples"] += 20;  // Updating the number of apples in inventory

$prod = "Apples";  // A product to be checked
echo "Total " . $prod . " in stock: " . $storeInventory[$prod] . "\n";

// Check if a product is in stock
$prod = "Mangoes";
if (array_key_exists($prod, $storeInventory)) {  // If mangoes exist in inventory
    echo $prod . " are in stock.\n";
} else {  // If mangoes don't exist in inventory
    echo $prod . " are out of stock.\n";
}
?>

Introduction and Goal Setting

Real-World Scenarios Calling for Associative Arrays

Solving Real-World Task 1: Cataloging Books in a Library

Solving Real-World Task 2: Counting Votes in an Election

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Solving Real-World Task 3: Tracking Store Inventories

Lesson Summary and Practice