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Variable is nothing more than a name of
data storage location in computer memory. Variables are used for storing values,
like text strings, numbers or arrays.
Syntax: Declaring a variable in PHP.
$Variable_Name = value;
PHP is a loosely Typed Language:
In PHP, a variable does not need to be declared before assigning a value to it.
In the above example, you see that you do not have to tell PHP, which types of
variable it 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 or define the type and name of the variable before using it.
Let’s we have an example, how to use variables in PHP script.
<html>
<head>
<title>PHP Variables</title>
</head>
<body>
<?php
// int
type variable
$intVar
=
1024;
// string
type
variable
$stringVar
="Hello";
// char type
varaible
$charVar
=
'A';
// float type
variable
$floatVar
=
102.5260;
echo
"This is integer varaible";
echo $intVar."</br>" ;
echo
"This is string variable :";
echo $stringVar."</br>" ;
echo
"This is char variable :";
echo $charVar."</br>" ;
echo
"This is float variable :";
echo $floatVar."</br>";
?>
</body>
</html>
Desired output is:
Naming Rule for declaring variables in PHP:
There is some rule to specify variables in PHP. The rules are…
1.
Variables name must start with letter or ‘_’
(Underscore).
2.
A variables name should not contains spaces. If a
variable name is more than one word, it should be separated with ‘_’
(Underscore) (such as $var_name) or use capitalization word (such as $varName).
3.
A variables name can only contain alpha-numeric
character (like $v123ar) and underscore.
Example:
Let’s we have an example, Declaring alphanumeric, underscore variable
etc.
<html>
<head>
<title>Variable Convention</title>
</head>
<body>
<?php
//
Declaring
'_' (underscore)
variable
$f_name
=
"Arun singh";
//
Declaring
alpha-numeric
variables
$roll123no
=
123456;
//
print
underscore
variable
echo $f_name ;
//
print
alph-numeric
varaible
echo $roll123no ;
?>
</body>
</html>
Desired output is:
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