PHP Variables

Variables are used to store data numbers, text like string. the variable in PHP can change according to the script PHP Variables Naming Rules. But some important information to you know about variables:

PHP variable does not need to declare before the addition of value to it.

PHP automatically converts the variable to its correct data type according to value.

In PHP assignment operator (=) used to assign value to a variable.

Every variable in PHP Start with a dollar ($) symbol

PHP is a loose type of language

Variable declare as:  $var_name=value.

When variable contain a string:

<?PHP

$txt= “Hello”;

$x=20;

?>

Naming Rules of PHP Variables

Variable start with  letter or  underscore”_”

Variable name only contains an alphanumeric character or underscore”_”(A to Z 0,9)

Space in the variable name not allowed

PHP names are case sensitive

If variable name more than one word in this situation it should be separate underscore”_”

For Example:

<?PHP

Declare a variable in PHP

$txt=” Hello”;

$num=10;

// when display variable value

Echo$txt;

// Output: Hello

Echo$num;    // Output 10

?>

PHP Variable Scope

PHP variable declared anywhere in the script

Three types of variable scope

1.local 

Local scope can only access within function

2.Global

Global scope can only access outside the function

3.Static

Static keyword first declare the variable PHP Variables Naming Rules

Global Variable Example:

<?php

$x=5;

$y=6;

Function test(){

Global $x,$y;

$y=$x+$y;

}

Test();

Echo$y;

?>

The output is: 15

?>

local Variable Example:

<?php

Function text(){

Echo”<p>Inside fuction:</p>”;

?>

static Variable Example:

<?php

function myTest(){

static $x=0;

echo $x;

$x++;

}

myText();

myText();

myText();

?>