09/11/2011

PHP Variables

Biến trong PHP




Biến dùng để lưu thông tin.

Biến trong PHP

Biến được dùng để lưu thông tin, như chuỗi, số hoặc mảng.
Tất cả các biến phải được bắt đầu bằng dấu $.
Ví dụ:
$var_name = value;

Ví dụ:
<?php
$txt="Hello World!";
$x=16;
?>


PHP is a Loosely Typed Language

In PHP, a variable does not need to be declared before adding a value to it.
In the example above, you see that you do not have to tell PHP which data type the variable is.
PHP automatically converts the variable to the correct data type, depending on its value.
In a strongly typed programming language, you have to declare (define) the type and name of the variable before using it.
In PHP, the variable is declared automatically when you use it.

Naming Rules for Variables

  • A variable name must start with a letter or an underscore "_"
  • A variable name can only contain alpha-numeric characters and underscores (a-z, A-Z, 0-9, and _ )
  • A variable name should not contain spaces. If a variable name is more than one word, it should be separated with an underscore ($my_string), or with capitalization ($myString)

Không có nhận xét nào:

Đăng nhận xét