Category Archives: PHP
PHP Tutorials
Variables
Variables:
Variables are named “containers” that allow you to store a value, like text strings, numbers or arrays. This value can then be used by other parts of the application, simply by referring to the variable’s name. For example, the application could display the contents of the variable to the user. When a variable is declared, it can be used over and over again in your script. The variable name is case-sensitive.
All variables in PHP start with a $ sign symbol.
Variable names can be any length.
Uppercase and lowercase letters are not same.
Ex: $$var_name = value;
Ex: <? Php
$my Variable =”Welcome to PHP Tutorials”;
Echo $my Variable;
?>
Ex: <!–? Php–>
$ Variable 1 =4;
$ Variable 2 =5;
$ Variable 3 =$ Variable 1+$ Variable 2;
?>
New PHP programmers often forget the $$ sign at the beginning of the variable. In that case it will not work.
Ex:
<!–? Php–>
$ txt=”Hello world”;
$ x=16;
?>
Let’s try creating a variable containing a string, and a variable containing a number;
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).
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