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@JeffreyWay

JeffreyWay/homework-solution.php

Created September 29, 2022 17:36
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PHP for Beginners, Episode 9 - Lambdas and Flexibility
Raw
homework-solution.php
<!doctype html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Demo</title>
</head>
<body>
<?php
$books = [
[
'name' => 'Do Androids Dream of Electric Sheep',
'author' => 'Philip K. Dick',
'releaseYear' => 1968,
'purchaseUrl' => 'http://example.com'
],
[
'name' => 'Project Hail Mary',
'author' => 'Andy Weir',
'releaseYear' => 2021,
'purchaseUrl' => 'http://example.com'
],
[
'name' => 'The Martian',
'author' => 'Andy Weir',
'releaseYear' => 2011,
'purchaseUrl' => 'http://example.com'
],
];
$filteredBooks = array_filter($books, function ($book) {
return $book['releaseYear'] >= 1950 && $book['releaseYear'] <= 2020;
});
?>
<ul>
<?php foreach ($filteredBooks as $book) : ?>
<li>
<a href="<?= $book['purchaseUrl'] ?>">
<?= $book['name']; ?> (<?= $book['releaseYear'] ?>) - By <?= $book['author'] ?>
</a>
</li>
<?php endforeach; ?>
</ul>
</body>
</html>
Raw
index.php
<!doctype html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Demo</title>
</head>
<body>
<?php
$books = [
[
'name' => 'Do Androids Dream of Electric Sheep',
'author' => 'Philip K. Dick',
'releaseYear' => 1968,
'purchaseUrl' => 'http://example.com'
],
[
'name' => 'Project Hail Mary',
'author' => 'Andy Weir',
'releaseYear' => 2021,
'purchaseUrl' => 'http://example.com'
],
[
'name' => 'The Martian',
'author' => 'Andy Weir',
'releaseYear' => 2011,
'purchaseUrl' => 'http://example.com'
],
];
$filteredBooks = array_filter($books, function ($book) {
return $book['author'] === 'Andy Weir';
});
?>
<ul>
<?php foreach ($filteredBooks as $book) : ?>
<li>
<a href="<?= $book['purchaseUrl'] ?>">
<?= $book['name']; ?> (<?= $book['releaseYear'] ?>) - By <?= $book['author'] ?>
</a>
</li>
<?php endforeach; ?>
</ul>
</body>
</html>
@MatimotTheTimoters
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MatimotTheTimoters commented Oct 26, 2025 

<?php

/* __________________________________________________
Array Filter
Use PHP's array_filter function to filter the list books to only those written by "Andy Weir."
*/

$books = [
    [
        'name' => 'Do Androids Dream of Electric Sheep',
        'author' => 'Philip K. Dick',
        'releaseYear' => 1968,
    ],
    [
        'name' => 'Project Hail Mary',
        'author' => 'Andy Weir',
        'releaseYear' => 2021,
    ],
    [
        'name' => 'The Martian',
        'author' => 'Andy Weir',
        'releaseYear' => 2011,
    ],
];

$filteredBooks = array_filter($books, function($book) {
    return $book['author'] === 'Andy Weir';
});

/* __________________________________________________
Where Between
Filter the books to only the ones that were originally published between the years 1950 and 2000.
*/

$books = [
    [
        'name' => 'Do Androids Dream of Electric Sheep',
        'author' => 'Philip K. Dick',
        'releaseYear' => 1968,
    ],
    [
        'name' => 'Project Hail Mary',
        'author' => 'Andy Weir',
        'releaseYear' => 2021,
    ],
    [
        'name' => 'The Martian',
        'author' => 'Andy Weir',
        'releaseYear' => 2011,
    ],
];

// Hint - the PHP equivalent of "and" is &&.
function filter($items, callable $callback) {
    $filteredItems = [];

    foreach ($items as $item) {
        if ($callback($item)) {
            $filteredItems[] = $item;
        }
    }

    return $filteredItems;
}

$filteredBooks = filter($books, fn($book) => {
    $bookWithinRange = ($book['releaseYear'] >= 1950) &&
                       ($book['releaseYear'] <= 2000);
    if ($bookWithinRange) {
        return $book;
    }
});

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