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390 lines
6.1 KiB
390 lines
6.1 KiB
# PHP
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## Setup
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1. Download [MAMP] (https://www.mamp.info/en/downloads/)
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1. Double click .pkg file and follow prompts
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1. Double click /Applications/MAMP/MAMP
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1. Tell MAMP to where your files are
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- Click on Preferences
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- Click on Web Server
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- Click the folder icon next to "Document Root" and find a suitable directory to work out of
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- Click OK
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1. In your Document Root, create `index.php`.
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1. Go to <http://localhost:8888/>
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- If no file is specified in the URL after the port, MAMP will look for `index.php`
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1. Error logs are in /Applications/MAMP/logs/
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- use `tail -f php_error.log` to watch the end of the log file in case something breaks
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1. MAMP stands for Mac, Apache, MySQL, PHP
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- Mac
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- Your OS
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- Apache
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- A pre-build web server that serves static files
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- It is extendable with various modules that allows it to do many things easily
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- MySQL
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- Your Database
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- PHP
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- A module for Apache that allows it to serve dynamic data
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## Basics
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### Tags
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Because this is all run on top of Apache, the initial assumption is that we're serving static HTML files
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- We need `<?php ?>` tags to show that we're writing PHP
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- Think of this as if Apache/PHP is server.js and we're writing EJS
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Instead of `<%= %>` you have `<?= ?>` or `<?php echo ?>`
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Instead of `<% %>` you have `<?php ?>`
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### Comments
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```php
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// single line comment
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```
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```php
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/*
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multi
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line
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comment
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*/
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```
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### Declaring/Assigning variables
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Use a $ before a variable name to tell php it is a variable. Assignment is standard.
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```php
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<?php
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$my_first_var; //declare
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$my_first_var = 2; //assignment
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$my_second_var = 3; //declare and assign
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echo $my_first_var; //print this variable to the page
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echo $my_second_var; //print this variable to the page
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?>
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```
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### Data Types
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PHP has the following basic data types:
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Strings:
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```php
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<?php
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$x = "my string";
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var_dump($x);
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?>
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```
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Integers:
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```php
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<?php
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$x = 5985;
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var_dump($x);
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?>
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```
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Floats:
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```php
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<?php
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$x = 10.365;
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var_dump($x);
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?>
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```
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Booleans:
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```php
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<?php
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$x = true;
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var_dump($x);
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?>
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```
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Arrays:
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```php
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<?php
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$cars = array("Volvo","BMW","Toyota");
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var_dump($cars);
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?>
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```
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NULL:
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```php
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<?php
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$x = null;
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var_dump($x);
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?>
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```
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### String Operators
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Use a `.` or `.=` to combine strings. Works just like `+` and `+=`
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```php
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<?php
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$first_part = "first part";
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$second_part = "second part";
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$concatenation = $first_part . " " . $second_part; //combine strings
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$concatenation .= ". Appended value"; //append strings
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echo $concatenation;
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?>
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```
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Some kinds of string interpolation work:
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```php
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<?php
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$x = 5;
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echo "I have $x pizzas";
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?>
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```
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### Arithmetic Operators
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```php
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<?php
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echo 1 + 1; //2
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echo 2 - 1; //1
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echo 3 * 2; //6
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echo 12 / 3; //4
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echo 5 % 2; //1 modulus
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echo 2 ** 3 //8 exponents
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?>
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```
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### Increment/Decrement Operators
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```php
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<?php
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$x = 2;
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$x++; //increment by 1;
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echo $x;
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$x--; //decrement by 1;
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echo $x;
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?>
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```
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### Assignment Operators
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```php
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<?php
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$my_var = 1;
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echo $my_var;
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$my_var += 3; //$my_var = $my_var + 3;
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echo $my_var;
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$my_var -= 2; //$my_var = $my_var - 2;
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echo $my_var;
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$my_var *= 2; //$my_var = $my_var * 2;
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echo $my_var;
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$my_var /= 2; //$my_var = $my_var / 2;
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echo $my_var;
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?>
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```
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## Conditionals
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### Formats
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The traditional format works great:
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```php
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<?php
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$x = 1;
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if($x > 2){
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echo "x > 2";
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}
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elseif($x < 2){
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echo "x < 2";
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}
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else{
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echo "x == 2";
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}
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?>
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```
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If you have html and don't want to have lines that look like `<?php } ?>`, you can use the following style of if/else:
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```php
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<?php $x = 1; ?>
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<?php if($x > 2): ?>
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<code>x > 2</code>
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<?php elseif($x < 2): ?>
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<code>x < 2</code>
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<?php else: ?>
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<code>x == 2</code>
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<?php endif; ?>
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```
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### Comparison Operators
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Equality:
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```php
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<?php
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$x == $y; //equal
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$x === $y; //identical
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$x != $y; //not equal
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$x !== $y; //not identical
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?>
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```
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Arithmetic:
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```php
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<?php
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$x < $y; //less than
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$x > $y; //greater than
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$x <= $y; //less than or equal to
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$x >= $y; //greater than or equal to
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?>
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```
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### Logical Operators
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```php
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<?php
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true && false //AND operator
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true || false //OR operator
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?>
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```
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## Arrays
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### Indexed Arrays
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Standard array functionality
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```php
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<?php
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$cars = array("Volvo", "BMW", "Toyota");
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$cars[4] = 'asdf'; //can be in indexes that don't yet exist
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$cars[] = "added to end"; //pushes onto array
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echo "I like " . $cars[0] . ", " . $cars[4] . " and " . $cars[5] . "."; //access arrays normally
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echo count($cars); //prints length of array
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print_r($cars); //prints contents of array in nicer format than var_dump
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?>
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```
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### Associative Arrays (hashes)
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These are very similar to JavaScript objects, but are accessed like arrays:
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```php
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<?php
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$age = array("Peter" => 35, "Ben" => 37, "Joe" => "43"); //declare
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$age["Bob"] = 105; //add at a new position
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echo "Bob is " . $age['Bob'] . " years old.";
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?>
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```
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## Loops
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### While
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```php
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<?php
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$x = 1;
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while($x <= 5) {
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echo "The number is: $x <br/>";
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$x++;
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}
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?>
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```
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Alternative syntax:
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```php
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<ul>
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<?php $x = 1;?>
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<?php while($x <= 5): ?>
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<li><?= $x ?></li>
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<?php $x++ ?>
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<?php endwhile; ?>
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</ul>
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```
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### For
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```php
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<?php
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for ($x = 0; $x <= 10; $x++) {
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echo "The number is: $x <br/>";
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}
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?>
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```
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Alternative syntax:
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```php
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<ul>
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<?php for ($x = 0; $x <= 10; $x++): ?>
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<li>The number is: <?= $x ?></li>
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<?php endfor; ?>
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</ul>
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```
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### Foreach
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This is like `for of` in JS:
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```php
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<?php
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$colors = array("red", "green", "blue", "yellow");
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foreach ($colors as $key => $value) {
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echo $key . ": $value <br/>";
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}
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?>
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```
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Alternative syntax:
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```php
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<?php $colors = array("red", "green", "blue", "yellow"); ?>
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<?php foreach ($colors as $key => $value): ?>
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<?= $key ?>: <?=$value?><br/>
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<?php endforeach ?>
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```
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This works for associative arrays:
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```php
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<?php
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$ages = array("Peter" => 35, "Ben" => 37, "Joe" => "43");
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foreach ($ages as $key => $value) {
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echo $key . ": $value <br/>";
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}
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?>
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```
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Alternative syntax:
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```php
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<?php $ages = array("Peter" => 35, "Ben" => 37, "Joe" => "43"); ?>
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<?php foreach ($ages as $key => $value): ?>
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<?= $key ?>: <?=$value?> <br/>
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<?php endforeach ?>
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```
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## Functions
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```php
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<?php
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function greet($name) {
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echo "Hello $name";
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}
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greet("Matt"); // call the function
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?>
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```
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