Overview/Notes

• Lots of built in functions
• Easy to learn
• Object oriented

Basics

Syntax is very simple, similar to that of Python or other C based languages. Variables are created by a simple $ in front of the name of the variable. Each line must end in a semi-colon.

<?php

$new_variable = "Hello World"; 
echo $new_variable;

?>

To display to screen we use the “echo” function, print() is also available

Data Types

We have a few to choose from: - String - Integer - Float/Double - Array - Object - NULL - Resource We can use the built in function “var_dump()” to find the data type of a variable.

<?php

$x = 200;
var_dump($x);

?>

---Output--- 

Int(200)

Strings are important! Because PHP is a hypertext markdown language, commonly used in conjunction with HTML. In PHP we can use HTML tags as if we were using them in HTML. I find it to be very convenient and interesting.

So for example, I often use <br> to separate outputs and make new lines.

<?php

$x = "Hello";
$y = "World";

echo "$x<br>$y";

?>

---Output---

Hello  
World

String Functions

• strlen() - returns the length of given string
• str_word_count() - returns the amount of words within the given string
• strpos(“string”, “word to find”) - returns the position of search word, if word not in string, FALSE is returned
• strtoupper() - puts all characters in string into caps
• strtolower() - all characters become lower case
• str_replace(“word to find”, “word to replace with”, string) - replaces characters in a string
• strrev() - reverses string
• trim() - removes any surrounding spaces in string
• explode(“separator”, string) - splits string into array

<?php

$x = "Hello World!";
$y = explode(" ", $x);

print_r($y);

?>
---Output---

Array ( [0] => Hello [1] => World! )

String Manipulation

String manipulation is pretty straight forward

Concatenation To combine strings we can use the ’ . ’ operator as well as a few other options. I prefer the 3rd option, its easier.

</php

$x = "Hello";
$y = "World";
$z = $x . $y;
echo $z;

---Output---

HelloWorld

-=-=-=-=-=-=-=-=-=-=-

$x = "Hello";
$y = "World";
$z = $x . " " . $y;
echo $z;

---Output---

Hello World

-=-=-=-=-=-=-=-=-=-=-

$x = "Hello";
$y = "World";
$z = "$x $y";
echo $z;

---Output---

Hello World

Objects are important too, sorta. Objects are just items of a class, so for example

<?php

class Car {
  public $color;
  public $model;
  public function __construct($color, $model) {
    $this->color = $color;
    $this->model = $model;
  }
  public function message() {
    return "My car is a " . $this->color . " " . $this->model . "!";
  }
}

$myCar = new Car("red", "Volvo");
var_dump($myCar);

?>

The object in this example is $myCar. $myCar belongs to the “Car” class and holds attributes based on it.