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PHP Build a Simple PHP Application Integrating with PayPal Array Keys

Juan Correa
Juan Correa
3,451 Points

I don't know whats wrong with this: <?php foreach($books as $book) { $isbn = $book['ISBN']; print_r($isbn); ?>

Why is my code wrong? It adds each book ISBN to the variable $isbn, when I use the print_r command I see all the ISBN numbers. Please help me!

books.php
<?php

$books[1] = array("ISBN"=>"978-0743261690", "title"=> "Gilgamesh");
$books[2] = array("ISBN"=>"978-0060931957", "title"=> "The Odyssey");
$books[3] = array("ISBN"=>"978-0192840509", "title"=> "Aesop's Fables");
$books[4] = array("ISBN"=>"978-0520227040", "title"=> "Mahabharta");
$books[5] = array("ISBN"=>"978-0393320978", "title"=> "Beowulf");

?><html>
<head>
    <title>Five Great Books</title>
</head>
<body>
    <h1>Five Great Books</h1>
    <ul>
        <?php foreach($books as $book) { ?>
            <li><?php $isbn = $book['ISBN'];
              print_r($isbn);?></li>
        <?php } ?>
    </ul>
</body>
</html>

2 Answers

First of all - You shouldn't change the original array that is given to you. You can access the key of each element with a little change in your "foreach" loop. It goes as such:

foreach ($books as $isbn => $book) {
 ...some code...
}

What this does is the following - it stores the key in a variable called $isbn and the element itself in $book (in this case the name of the book). From here you can access both the isbn of a book (through the $isbn variable) and it's title.

So when you're asked to print both the title and the isbn it goes like this:

<?php foreach($books as $isbn => $book) { ?>
  <li><?php echo $book . " (" . $isbn . ")"; ?></li>
<?php } ?>

Once again, leave the array as such:

$books["978-0743261690"] = "Gilgamesh";
$books["978-0060931957"] = "The Odyssey";
$books["978-0192840509"] = "Aesop's Fables";
$books["978-0520227040"] = "Mahabharta";
$books["978-0393320978"] = "Beowulf";
Juan Correa
Juan Correa
3,451 Points

Thank you for your help Kristian!

You're very welcome. If you need anything else, be sure to ask.