What are the different scopes of variables in PHP ?
Variable Scopes: The scope of a variable is defined as its extent in the program within which it can be accessed, i.e. the scope of a variable is the portion of the program within which it is visible or can be accessed. Depending on the scopes, PHP has three variable scopes.
Local variables: The variables declared within a function are called local variables to that function and have their scope only in that particular function. In simple words, it cannot be accessed outside that function. Any declaration of a variable outside the function with the same name as that of the one within the function is a completely different variable. For now, consider a function as a block of statements.
Example:
PHP
<?php
$num = 60;
function local_var() {
$num = 50;
echo "local num = $num <br>" ;
}
local_var();
echo "Variable num outside local_var() function is $num \n" ;
?>
|
Output:
local num = 50
Variable num outside local_var() function is 60
Global variables: The variables declared outside a function are called global variables. These variables can be accessed directly outside a function. To get access within a function, we need to use the “global” keyword before the variable to refer to the global variable.
Example:
PHP
<?php
$num = 20;
function global_var() {
global $num ;
echo "Variable num inside function : $num \n" ;
}
global_var();
echo "Variable num outside function : $num \n" ;
?>
|
Output:
Variable num inside function : 20
Variable num outside function : 20
Static variable: It is the characteristic of PHP to delete the variable, once it completes its execution and the memory is free. But sometimes we need to store the variables even after the completion of function execution. To do this, we use static keywords and the variables are called static variables. PHP associates a data type depending on the value for the variable.
Example:
PHP
<?php
function static_var() {
static $num = 5;
$sum = 2;
$sum ++;
$num ++;
echo $num , "\n" ;
echo $sum , "\n" ;
}
static_var();
static_var();
?>
|
Output:
6
3
7
3
Last Updated :
06 May, 2022
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