Getting started with php
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This document provides an introduction to PHP for beginners. It discusses what PHP is, why it should be used, examples of basic PHP code, and some key PHP concepts like arrays, functions, and loops. The document contains examples to demonstrate how to output text, get data from users, create and access arrays, write conditionals and loops, define and call functions, and pass arguments to functions. The goal is to get readers started with PHP by explaining the basics in a simple way through examples.
![$_GET Variables come from the URL
Bad:
<?php
$name = $_GET['name'];
?>
NEVER trust data from your users!
Good:
<?php
if(isset($_GET['name'])){
$name = filter_var($_GET['name'],FILTER_SANITIZE_STRING);
}
?>
Getting Data from the User](https://image.slidesharecdn.com/gettingstartedwithphp-130927093105-phpapp01/85/Getting-started-with-php-9-320.jpg)
![So what is happening?
● First we check if the name exists by
looking at $_GET[‘name’]
○ if(isset($_GET['name'])){
● If it does exist, we pass it to a function to
sanitize the input and set the results equal
to $name
○ $name = filter_var($_GET['name'],FILTER_SANITIZE_STRING);
Getting Data from the User](https://image.slidesharecdn.com/gettingstartedwithphp-130927093105-phpapp01/85/Getting-started-with-php-10-320.jpg)
![Simple Arrays:
<?php
$fruit = array();
$fruit[] = 'apple';
$fruit[] = 'pear';
$fruit[] = 'orange';
$fruit[] = 'lemon';
$fruit[] = 'pineapple';
?>
Arrays - associating values to keys](https://image.slidesharecdn.com/gettingstartedwithphp-130927093105-phpapp01/85/Getting-started-with-php-15-320.jpg)
![$food = array();
$food['fruit'] = array();
$food['fruit'][] = 'apple';
$food['fruit'][] = 'pear';
$food['fruit'][] = 'orange';
$food['fruit'][] = 'lemon';
$food['fruit'][] = 'pineapple';
$food['meat'] = array();
$food['meat'][] = 'bacon';
$food['meat'][] = 'steak';
$food['meat'][] = 'chicken';
$food['meat'][] = 'fish';
Multidimensional Arrays - Ex 5](https://image.slidesharecdn.com/gettingstartedwithphp-130927093105-phpapp01/85/Getting-started-with-php-16-320.jpg)
![While loops perform the action while a
condition is met and then stops.
$fruit_count = count($fruit);
$f = 0;
while ($f < $fruit_count){
echo '<li>' . $fruit[$f] . '</li>';
$f++;
}
While Loops - Example 8](https://image.slidesharecdn.com/gettingstartedwithphp-130927093105-phpapp01/85/Getting-started-with-php-20-320.jpg)
![function getFruit(){
$fruit = array();
$fruit[] = 'apple';
$fruit[] = 'pear';
$fruit[] = 'orange';
$fruit[] = 'lemon';
$fruit[] = 'pineapple';
return $fruit;
}
FUNctions - Example 9](https://image.slidesharecdn.com/gettingstartedwithphp-130927093105-phpapp01/85/Getting-started-with-php-21-320.jpg)
Getting started with php
- 2. Joe Ferguson - [email protected] Professionally ● Web Developer at RocketFuel ● PHP / LAMP Focused Semi Professional ● Co-Organizer for MemphisPHP.org ● MidsouthMakers - Hackerspace Leader ● HACKmemphis.com Organizer Who is this guy?
- 3. It’s a recursive anagram… PHP: Hypertext Preprocessor is a widely used, general- purpose scripting language that was originally designed for web development to produce dynamic web pages What is PHP?
- 4. ● Widespread Availability ○ PHP is now installed on more than 244 million websites and 2.1 million web servers (Source: Wikipedia) ● Ease of use. ○ Extremely simple for newcomers ○ Advanced features for professional programmers ○ Looslely typed ● Great Community Support ● Many corporations throwing support behind PHP projects Why use PHP?
- 5. Who uses it? What runs on PHP? ...and many, MANY others
- 6. <html> <head> <title>Example 1 - Getting Started with PHP<</title> </head> <body> <?php echo '<p>Hello World</p>'; ?> </body> </html> Jumping into PHP - Example 1
- 7. You can add any content to a PHP file. Anything not between PHP tags is ignored by PHP. Using echo, you can print from PHP. As example 1 shows, even PHP. Example 1 - Basic HTML + PHP
- 8. PHP is very easy to pick up and run with. This is one of the main reasons it is so widespread. Looks easy right?
- 9. $_GET Variables come from the URL Bad: <?php $name = $_GET['name']; ?> NEVER trust data from your users! Good: <?php if(isset($_GET['name'])){ $name = filter_var($_GET['name'],FILTER_SANITIZE_STRING); } ?> Getting Data from the User
- 10. So what is happening? ● First we check if the name exists by looking at $_GET[‘name’] ○ if(isset($_GET['name'])){ ● If it does exist, we pass it to a function to sanitize the input and set the results equal to $name ○ $name = filter_var($_GET['name'],FILTER_SANITIZE_STRING); Getting Data from the User
- 11. ● isset ● empty ● filter_var ● arrays ● strings ● omgwtf! The best PHP resources: ● phptherightway.com ● php.net I can’t keep track of all this!
- 12. PHP Specification Request (PSR) The Framework Interop Group: ● PSR-0 ● PSR-1 ● PSR-2 Other Styles: ● PEAR Coding Standards ● Zend Coding Standards OMG your { are on the wrong line!
- 13. There are subtle differences among the PSR coding styles approved by the FIG. If you’re wanting to maximize your reusability: pick a PSR similar to the code you are working with. Most projects won’t take code if it doesn’t match the style they have adopted. Why so many? What do I use?
- 14. Strings ● echo ‘PHP is my favorite language’; ● $variable = ‘PHP is amazing’; ● echo "PHP! you'll be astonished"; ● echo 'PHP! you'll be astonished'; Concatenation ● echo "Hello, " . $prefix . " " . $name; Single quote strings do not get parsed. Double quote strings get parsed. Are slower than single quote strings because of this. Before we get too complicated:
- 15. Simple Arrays: <?php $fruit = array(); $fruit[] = 'apple'; $fruit[] = 'pear'; $fruit[] = 'orange'; $fruit[] = 'lemon'; $fruit[] = 'pineapple'; ?> Arrays - associating values to keys
- 16. $food = array(); $food['fruit'] = array(); $food['fruit'][] = 'apple'; $food['fruit'][] = 'pear'; $food['fruit'][] = 'orange'; $food['fruit'][] = 'lemon'; $food['fruit'][] = 'pineapple'; $food['meat'] = array(); $food['meat'][] = 'bacon'; $food['meat'][] = 'steak'; $food['meat'][] = 'chicken'; $food['meat'][] = 'fish'; Multidimensional Arrays - Ex 5
- 17. ● We know that PHP is awesome ● We know A LOT of people use PHP ● We’ve greeted the world of PHP ● We have seen how to get data from users ● We are absolute EXPERTS at Arrays The Story So Far
- 18. Conditions $name = 'Joe'; //$name = 'Bill the pony'; if($name == 'Joe'){ echo '<p>Hello Joe, welcome back</p>'; } else { echo '<p>Hello ' . $name . '</p>'; } Putting it together… Example 6
- 19. Foreach steps through each item. You perform some action on each item. foreach($fruit AS $key => $value){ echo '<li>' . $value . '</p>'; } For Loops - Example 7
- 20. While loops perform the action while a condition is met and then stops. $fruit_count = count($fruit); $f = 0; while ($f < $fruit_count){ echo '<li>' . $fruit[$f] . '</li>'; $f++; } While Loops - Example 8
- 21. function getFruit(){ $fruit = array(); $fruit[] = 'apple'; $fruit[] = 'pear'; $fruit[] = 'orange'; $fruit[] = 'lemon'; $fruit[] = 'pineapple'; return $fruit; } FUNctions - Example 9
- 22. Using the previous getFruit function: $fruit = getFruit(); $fruit is now an array created by the function Using Functions - Example 9
- 23. ● You can pass data into an array by adding arguments function getFruitOrMeat($fruit_or_meat){ … } $fruit_or_meat is data we are passing into the getFruitOrMeat function Function Arguments Example 10
- 24. The best PHP resources: ● phptherightway.com ● php.net Online Learning: ● codecademy.com ● php.net/manual/en/getting-started.php More Information