PHP Variables

PHP Variable is the name of memory location used to hold the data.  In PHP, variable starts with $ symbol. Rules for PHP Variables.

• Variable starts with $ sign.
• Variable name must start with a letter or the underscore character.
• Variable name can contain alpha-numeric character (A-Z. 0-9).
• Variable name are case-sensitive ($name and $NAME are two different variables).

Example

<?php
$name = "RasmusLerdorf";
echo "PHP Father:  $name";
?>

Output PHP Father: RasmusLerdorf In PHP, there are three variables:

• local variable
• global variable
• static variable

Local variable PHP local variable is declared inside a function. It has local scope and can be accessed within the function. Example:

<?php
function fun() {
    $x = 10; // local scope
echo "<p> x variable inside of the function: $x</p>";
}
fun();
// Generate an error because x is outside the function
echo "<p> x variable outside of the function: $x</p>";
?>

Output x variable inside of the function: 10 Notice: Undefined variable: x in C:\xampp\htdocs\crud\HELLO.PHP on line 8 x variable outside of the function:  Global Variable The Global is a keyword that is used to access global variable within a function. Example:

<?php
$x = 10; // global variable
$y = 5;  // global variable
$z=5; // global variable
function fun() {
global $x, $y,$z;
    $y = $x * $y+$z;
}
fun();
echo $y; // outputs 55
?>

Output 55 Static variable Php static is a keyword that is used to create a static variable. Static variable is not be deleted when a function is completed /executed. Example

<?php
function fun() {
static $val = 0;
echo $val;
    $val++;
}
fun();
echo "<br>";
fun();      // call function
echo "<br>";
fun();      // call function
echo "<br>";
?>

Output 0 1 2