parent
3766332db7
commit
5d14cc808b
@ -0,0 +1,261 @@
|
|||||||
|
#Intermediate PHP
|
||||||
|
|
||||||
|
## Functions
|
||||||
|
|
||||||
|
```php
|
||||||
|
<?php
|
||||||
|
function greet($name) {
|
||||||
|
echo "Hello $name";
|
||||||
|
}
|
||||||
|
|
||||||
|
writeMsg("Matt"); // call the function
|
||||||
|
?>
|
||||||
|
```
|
||||||
|
|
||||||
|
## Convenience Methods
|
||||||
|
|
||||||
|
PHP has lots of global functions that will help you out:
|
||||||
|
|
||||||
|
### Strings
|
||||||
|
|
||||||
|
Count a string's length
|
||||||
|
|
||||||
|
```php
|
||||||
|
<?php
|
||||||
|
echo strlen("Hello world!"); // outputs 12
|
||||||
|
?>
|
||||||
|
```
|
||||||
|
|
||||||
|
Count number of words in a string
|
||||||
|
|
||||||
|
```php
|
||||||
|
<?php
|
||||||
|
echo str_word_count("Hello world!"); // outputs 2
|
||||||
|
?>
|
||||||
|
```
|
||||||
|
|
||||||
|
Reverse a string
|
||||||
|
|
||||||
|
```php
|
||||||
|
<?php
|
||||||
|
echo strrev("Hello world!"); // outputs !dlrow olleH
|
||||||
|
?>
|
||||||
|
```
|
||||||
|
|
||||||
|
Find a sub string in a string
|
||||||
|
|
||||||
|
```php
|
||||||
|
<?php
|
||||||
|
echo strpos("Hello world world!", "world"); // outputs 6
|
||||||
|
//search from the right
|
||||||
|
echo strrpos("Hello world world!", "world"); // outputs 12
|
||||||
|
?>
|
||||||
|
```
|
||||||
|
|
||||||
|
Replace text within a string
|
||||||
|
|
||||||
|
```php
|
||||||
|
<?php
|
||||||
|
echo str_replace("world", "Dolly", "Hello world!"); // outputs Hello Dolly!
|
||||||
|
?>
|
||||||
|
```
|
||||||
|
|
||||||
|
Get a substring based on character index
|
||||||
|
|
||||||
|
```php
|
||||||
|
<?php
|
||||||
|
//This gets all remaining characters starting at the index specified in the string (0 based, like an array)
|
||||||
|
echo substr("Hello world", 3); // outputs 'lo world'
|
||||||
|
|
||||||
|
//third param is length of string to retrieve
|
||||||
|
echo substr("Hello world", 3, 4); // outputs 'lo w'
|
||||||
|
?>
|
||||||
|
```
|
||||||
|
|
||||||
|
Turn a string into an array based on some delimiter:
|
||||||
|
|
||||||
|
```php
|
||||||
|
<?php
|
||||||
|
$the_string = "Some sentence goes here";
|
||||||
|
$string_array = explode(" ", $the_string);
|
||||||
|
var_dump($string_array);
|
||||||
|
?>
|
||||||
|
```
|
||||||
|
|
||||||
|
### Sorting Arrays
|
||||||
|
|
||||||
|
Various functions for sorting arrays. Can be done arithmetically or alphabetically, depending on content
|
||||||
|
|
||||||
|
- sort() - sort arrays in ascending order
|
||||||
|
- rsort() - sort arrays in descending order
|
||||||
|
- asort() - sort associative arrays in ascending order, according to the value
|
||||||
|
- ksort() - sort associative arrays in ascending order, according to the key
|
||||||
|
- arsort() - sort associative arrays in descending order, according to the value
|
||||||
|
- krsort() - sort associative arrays in descending order, according to the key
|
||||||
|
|
||||||
|
These functions affect the actual array they are called on.
|
||||||
|
|
||||||
|
```php
|
||||||
|
$cars = array("Volvo", "BMW", "Toyota");
|
||||||
|
sort($cars);
|
||||||
|
print_r($cars); //BMW, Toyota, Volvo
|
||||||
|
rsort($cars);
|
||||||
|
print_r($cars); //Volco, Toyota, BMW
|
||||||
|
```
|
||||||
|
|
||||||
|
Now with associative arrays:
|
||||||
|
|
||||||
|
```php
|
||||||
|
$ages = array("Peter" => 35, "Ben" => 37, "Joe" => "43");
|
||||||
|
asort($ages);
|
||||||
|
print_r($ages);
|
||||||
|
ksort($ages);
|
||||||
|
print_r($ages);
|
||||||
|
arsort($ages);
|
||||||
|
print_r($ages);
|
||||||
|
krsort($ages);
|
||||||
|
print_r($ages);
|
||||||
|
```
|
||||||
|
|
||||||
|
## Classes and Objects
|
||||||
|
|
||||||
|
### Public Members
|
||||||
|
|
||||||
|
```php
|
||||||
|
<?php
|
||||||
|
class Car {
|
||||||
|
public $wheels = 4; // public var can be accessed outside class definition
|
||||||
|
}
|
||||||
|
|
||||||
|
$my_car = new Car();
|
||||||
|
|
||||||
|
print_r($my_car);
|
||||||
|
$my_car->wheels = 3;
|
||||||
|
print_r($my_car);
|
||||||
|
?>
|
||||||
|
```
|
||||||
|
|
||||||
|
### Constructors
|
||||||
|
|
||||||
|
```php
|
||||||
|
<?php
|
||||||
|
class Car {
|
||||||
|
public $wheels;
|
||||||
|
public function __construct($num_wheels){ // runs at beginning of object creation
|
||||||
|
$this->wheels = $num_wheels;
|
||||||
|
}
|
||||||
|
}
|
||||||
|
$my_car = new Car(4);
|
||||||
|
print_r($my_car);
|
||||||
|
?>
|
||||||
|
```
|
||||||
|
|
||||||
|
### Protected Members
|
||||||
|
|
||||||
|
But what if you don't want someone to modify the number of wheels of a car after it is created?
|
||||||
|
You can set a method or member to `private` and any instance will not be able to read or write that value. It is only accessible from within the class itself
|
||||||
|
|
||||||
|
```php
|
||||||
|
<?php
|
||||||
|
class Car {
|
||||||
|
protected $wheels; // cannot be accessed outside class definition
|
||||||
|
|
||||||
|
//you must define public getters in order to see how many wheels a car has
|
||||||
|
public function getWheels(){
|
||||||
|
return $this->wheels;
|
||||||
|
}
|
||||||
|
|
||||||
|
public function __construct($num_wheels){
|
||||||
|
$this->wheels = $num_wheels;
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
$my_car = new Car(4);
|
||||||
|
echo $my_car->getWheels();
|
||||||
|
echo $my_car->wheels; //error: cannot access protected property
|
||||||
|
$my_car->wheels = 4; //error
|
||||||
|
?>
|
||||||
|
```
|
||||||
|
|
||||||
|
### Statics
|
||||||
|
|
||||||
|
You can have `static` members and methods that accessible only on the class itself, not on instances of the class.
|
||||||
|
|
||||||
|
```php
|
||||||
|
<?php
|
||||||
|
class Car {
|
||||||
|
protected $wheels;
|
||||||
|
public function getWheels(){
|
||||||
|
return $this->wheels;
|
||||||
|
}
|
||||||
|
public function __construct($num_wheels){
|
||||||
|
$this->wheels = $num_wheels;
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
class CarFactory{
|
||||||
|
static protected $cars = array(); // the array is protected
|
||||||
|
static public function create($num_wheels){
|
||||||
|
$new_car = new Car($num_wheels);
|
||||||
|
self::$cars[] = $new_car;
|
||||||
|
return $new_car;
|
||||||
|
}
|
||||||
|
static public function find($index){
|
||||||
|
return self::$cars[$index];
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
$my_car = CarFactory::create(2);
|
||||||
|
$my_car2 = CarFactory::create(4);
|
||||||
|
print_r($my_car);
|
||||||
|
print_r(CarFactory::find(1));
|
||||||
|
print_r(CarFactory::$cars); //errors out: protected
|
||||||
|
?>
|
||||||
|
```
|
||||||
|
|
||||||
|
### Inheritance
|
||||||
|
|
||||||
|
Protected members/methods can be used by inheriting classes, private members/methods cannot
|
||||||
|
|
||||||
|
```php
|
||||||
|
<?php
|
||||||
|
class Car {
|
||||||
|
protected $wheels; //accessible by child class, not outside class, though
|
||||||
|
private $engine_on = false; //unaccessible by child class
|
||||||
|
public function __construct($num_wheels){
|
||||||
|
$this->wheels = $num_wheels;
|
||||||
|
}
|
||||||
|
public function getWheels(){
|
||||||
|
return $this->wheels;
|
||||||
|
}
|
||||||
|
public function start(){
|
||||||
|
$this->engine_on = true;
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
class Humvee extends Car {
|
||||||
|
protected $armour = 10;
|
||||||
|
public function takeDamage($damage){
|
||||||
|
$this->armour -= $damage;
|
||||||
|
}
|
||||||
|
public function loseWheel(){
|
||||||
|
$this->wheels--; //can access parent class $wheels member because it is protected
|
||||||
|
}
|
||||||
|
//can extend parent's start function
|
||||||
|
public function start(){
|
||||||
|
parent::start(); //run parent's start function
|
||||||
|
//parent::$engine_on = false; //errors out: cannot access private member of parent
|
||||||
|
echo "WELCOME TO THE JUNGLE...";//then do something else
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
$my_humvee = new Humvee(6);
|
||||||
|
print_r($my_humvee);
|
||||||
|
$my_humvee->loseWheel();
|
||||||
|
print_r($my_humvee);
|
||||||
|
$my_humvee->takeDamage(6);
|
||||||
|
print_r($my_humvee);
|
||||||
|
$my_humvee->start();
|
||||||
|
print_r($my_humvee);
|
||||||
|
?>
|
||||||
|
```
|
||||||
Loading…
Reference in new issue