PHP Tutorials
PHP Introduction
PHP Install
PHP Syntax
PHP Echo/Print
PHP Comments
PHP Variables
PHP DataTypes
PHP Numbers
PHP Math
PHP Strings
PHP If..else
PHP Operators
PHP Loops
PHP Functions
PHP Forms
PHP Form Handling
PHP Form Validation
PHP Form Required
PHP Form Complete
PHP Advanced
PHP Include
PHP File Handling
PHP Cookies
PHP Sessions
PHP Filters
PHP JSON
PHP Exceptions
PHP OOP
PHP What is OOP
PHP OOP Classes/Objects
PHP Constructors
PHP Destructors
PHP Access Modifiers
PHP Interfaces
PHP Traits
PHP Iterables
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PHP Data Types
PHP Data Types
Variables can store data of different types, and different types of data can do different things.
PHP supports the following types of data:
- String
- Integer
- Float (floating point numbers - also called double)
- Boolean
- Array
- Object
- NULL
- Resource
PHP String
The alphabet unit is a sequence of letters, such as "Hello world!".
The character unit can be any text within the quotes. You can use one or two quotes:
Example
<?php
$x = "Hello world!";
$y = 'Hello world!';
echo $x;
echo "<br>";
echo $y;
?>
PHP Integer
The total data is a non-decimal number between -2,147,483,648 and 2,147,483,647.
Rules for integers:
- An integer must have at least one digit
- An integer must not have a decimal point
- An integer can be either positive or negative
- Integers can be specified in: decimal (base 10), hexadecimal (base 16), octal (base 8), or binary (base 2) notation
In the following example $ x is a whole number. The PHP function var_dump () returns the data type and value:
Example
<?php
$x = 5985;
var_dump($x);
?>
PHP Float
A float (a floating point number) is a number with a decimal point or a number in the descriptor form.
In the following example $ x is float. The PHP function var_dump () returns the data type and value:
Example
<?php
$x = 10.365;
var_dump($x);
?>
PHP Boolean
Boolean represents two possible situations: TRUE or FALSE.
$x = true;
$y = false;
Booleans are often used in conditional testing. You will learn more about conditional testing in the next chapter of this study.
PHP Array
The list saves multiple values for a single variable.
In the following example $ cars is the same member. The PHP function var_dump () returns the data type and value:
Example
<?php
$cars = array("Volvo","BMW","Toyota");
var_dump($cars);
?>
PHP Object
Classes and objects are two main elements of an object-focused program.
A classroom is a model of objects, and an object is a model of a class.
When each item is created, it inherits all the features and behaviors in the classroom, but each item will have different value structures.
Suppose we have a class called Car. The car can have properties such as model, color, etc. We can define variables like $ model, $ color, etc., to capture the values of these properties.
When individual items (Volvo, BMW, Toyota, etc.) are created, they inherit all the buildings and behaviors from the classroom, but each item will have different property values.
When you create a __construct () function, PHP will call this function automatically when you create an object from the classroom.
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("black", "Volvo");
echo $myCar -> message();
echo "<br>";
$myCar
= new Car("red", "Toyota");
echo $myCar -> message();
?>
PHP NULL Value
Null is a special data type that can have only one value: NULL.
The NULL data type variable is a variable without a given value.
Tip: If the exception is created out of value, it is automatically given NULL value.
Variables can also be specified by setting the value to NULL:
Example
<?php
$x = "Hello world!";
$x = null;
var_dump($x);
?>
PHP Resource
Special service type is not actual data type. Maintaining reference for activities and resources outside of PHP.
A common example of using a data center application is a website.
We will not talk about the type of service here, as it is an advanced topic.