A basic example of using user-defined PHP functions.
This tutorial will review how to use a series of user-defined functions for format data from a PHP array.
The functions.php file includes an array with data for three programming books. The array closely resembles data from a MySQL database.
Similar to the arrays, if, and loops examples, your code needs to output the three values. However, this time it will use some user-defined functions to ensure the prices are formatted properly and display the rating as stars instead of a plain number.
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Open up a new file and name it
functions.php. -
Add the following code to the new PHP file:
<!doctype html> <html> <head> <title>PHP Functions</title> </head> <body> <h1>PHP Functions</h1> <p>Use PHP echo, if statements, loops, and functions to output all three books.</p> <?php // ************************************************** // Do not edit this code // Define a multi dimensional array to store all of the books $books = array ( 0 => array ( 'name' => 'JavaScript and JQuery: Interactive Front-End Web Development', 'url' =>'https://www.chapters.indigo.ca/en-ca/books/javascript-and-jquery-interactive-front/9781118531648-item.html', 'image' => 'javascript-jquery.jpg', 'description' => 'Learn JavaScript and jQuery a nicer way.', 'rating' => 4, 'price' => '44.90', 'sale' => '39.90' ), 1 => array ( 'name' => 'Php For The Web: Visual Quickstart Guide', 'url' =>'https://www.chapters.indigo.ca/en-ca/books/php-for-the-web-visual/9780134291253-item.html', 'image' => 'php-web.jpg', 'description' => 'Learn PHP programming the quick and easy way!', 'rating' => 3, 'price' => '55.99', 'sale' => '' ), 2 => array ( 'name' => 'Beginning Node.js', 'url' =>'https://www.chapters.indigo.ca/en-ca/books/beginning-node-js/9781484201886-item.html', 'image' => 'beginning-nodejs.jpg', 'description' => 'A step-by-step guide to learning how to develope a Node.js application.', 'rating' => 5, 'price' => '65.90', 'sale' => '58.90' ), ); // ************************************************** // Loop through the array and display the link information foreach ($books as $book) { echo '<h2>'.$book['name'].'</h2>'; echo '<hr>'; } // Use the print_r function to view the contents of the array echo '<pre>'; print_r ($books); echo '</pre>'; ?> </body> </html>
Note
Do not edit the code between the stars.
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Before the
doctypetag create two functions. The first will accept one numeric paraemter and format it as a number using the format $.00.00. The second function will convert a rating t a series of visual start using HTML special chacaters. For example 3/5 would display ★★★☆☆. -
In the
bodysection add code that will display the three sets of book information using loops and the two functions defined in the previous step.
Note
Add each value from the arrays one at a time. Test your PHP after each new line of PHP.
Full tutorial URL:
https://codeadam.ca/learning/php-functions.html
- Visual Studio Code or Brackets (or any code editor)
- Filezilla (or any FTP program)
