Showing posts with label 04. PHP Variables. Show all posts
Showing posts with label 04. PHP Variables. Show all posts

Saturday, November 8, 2008

PHP Variables

Variables are used for storing values, such as numbers, strings
or function results, so that they can be used many times in a script.





Variables in PHP


Variables are used for storing a values, like text strings, numbers or
arrays.


When a variable is set it can be used over and over again in your script


All variables in PHP start with a $ sign symbol.


The correct way of setting a variable in PHP:





$var_name = value;

New PHP programmers often forget the $ sign at the beginning of the variable.
In that case it will not work.


Let's try creating a variable with a string, and a variable with a
number:





<?php
$txt = "Hello World!";
$number = 16;
?>





PHP is a Loosely Typed Language


In PHP a variable does not need to be declared before being set.


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 how they are set.


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.





Variable Naming Rules



  • 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 underscore ($my_string), or with
    capitalization ($myString)

Followers

 
template by free-web-template.blogspot.com