Online training and video tutorials
Enter     Registration
     Contacts

 
     
 
Max Azimov
St. Petersburg

Articles [97]

User's video [259]





PHP 5 Data Types
 
PHP Data Types
 
Variables can store data of different types, and different data types can do different things.
 
PHP supports the following data types:
  • String
  • Integer
  • Float (floating point numbers - also called double)
  • Boolean
  • Array
  • Object
  • NULL
  • Resource
 
PHP String
 
A string is a sequence of characters, like "Hello world!".
 
A string can be any text inside quotes. You can use single or double quotes:

 
Example
  1. <?php 
  2. $x = "Hello world!";
  3. $y = 'Hello world!';
  4. echo $x;
  5. echo "<br>"; 
  6. echo $y;
  7. ?>
 
PHP Integer
 
An integer data type 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 three formats: decimal (10-based), hexadecimal (16-based - prefixed with 0x) or octal (8-based - prefixed with 0)
In the following example $x is an integer. The PHP var_dump() function returns the data type and value:

 
Example
  1. <?php 
  2. $x = 5985;
  3. var_dump($x);
  4. ?>
 
PHP Float
 
A float (floating point number) is a number with a decimal point or a number in exponential form.
 
In the following example $x is a float. The PHP var_dump() function returns the data type and value:
 
 
Example
  1. <?php 
  2. $x = 10.365;
  3. var_dump($x);
  4. ?>
 
PHP Boolean
 
A Boolean represents two possible states: TRUE or FALSE.
 
$x = true;
$y = false;
 
Booleans are often used in conditional testing. You will learn more about conditional testing in a later chapter of this tutorial.

 
PHP Array
 
An array stores multiple values in one single variable.
 
In the following example $cars is an array. The PHP var_dump() function returns the data type and value:

 
Example
  1. <?php 
  2. $cars = array("Volvo","BMW","Toyota");
  3. var_dump($cars);
  4. ?>
 
You will learn a lot more about arrays in later chapters of this tutorial.

 
PHP Object
 
An object is a data type which stores data and information on how to process that data.
 
In PHP, an object must be explicitly declared.
 
First we must declare a class of object. For this, we use the class keyword. A class is a structure that can contain properties and methods:

 
Example
  1. <?php
  2. class Car {
  3.     function Car() {
  4.         $this->model = "VW";
  5.     }
  6. }
  7. // create an object
  8. $herbie = new Car();
  9. // show object properties
  10. echo $herbie->model;
  11. ?>
     
You will learn more about objects in a later chapter of this tutorial.
 

PHP NULL Value
 
Null is a special data type which can have only one value: NULL.
 
A variable of data type NULL is a variable that has no value assigned to it.
 
Tip: If a variable is created without a value, it is automatically assigned a value of NULL.
 
Variables can also be emptied by setting the value to NULL:

 
Example
  1. <?php
  2. $x = "Hello world!";
  3. $x = null;
  4. var_dump($x);
  5. ?>
 
PHP Resource
 
The special resource type is not an actual data type. It is the storing of a reference to functions and resources external to PHP.
 
A common example of using the resource data type is a database call.
 
We will not talk about the resource type here, since it is an advanced topic.


2016-12-08
572 views




 
     
 
Map      Distance education, online learning courses. Project PLANETSTUDY - distance learning online.
© 2012 PlanetStudy

Catalog.299.ru

The site is a media provider
Яндекс.Метрика
 
English USA
Australia Русский