The scope of the variable is the area within which the variable has been created. Based on this, a variable can either have a local scope, a global scope, or a static scope in PHP.
A variable that was created in the main body of the code and that can be accessed anywhere in the program is called a Global Variable. Global variables can be directly accessed or used in or outside of a function with the global keyword before the variable. However, we can also call them without the global keyword.
For Example:
<?php
$name = "Hello world"; // Global Variable
function global_var()
{
global $name;
echo "Variable inside the function: " . $name;
echo "</br>";
}
global_var();
echo "Variable outside the function: " . $name;
?>
Output:
Variable inside the function: Hello world
Variable outside the function: Hello world
A local variable is created within a function and can only be used inside the function. This means that these variables cannot be accessed outside the function, as they have local scope.
For Example:
<?php
function mytest()
{
$capital = "Delhi";
echo "Capital of India is: " . $capital;
}
mytest(); // Calling the function
// Using $capital outside the function will generate an error
echo $capital;
?>
Output:
Capital of India is: Delhi
Static Variable:
PHP has a feature that deletes the variable once it has finished execution and frees the memory. When we need a local variable that can store its value even after the execution, we use the static keyword before it, and the variable is called a static variable.
These variables only exist in a local function and do not get deleted after the execution has been completed.
For Example:
<?php
function static_var()
{
static $num1 = 3; // Static variable
$num2 = 6; // Non-static variable
// Increment in non-static variable which will increment its value to 7
$num1++;
// Increment in static variable which will increment its value to 4 after first execution and 5 after second execution
$num2++;
echo "Static: " . $num1 . "</br>";
echo "Non-static: " . $num2 . "</br>";
}
// First function call
static_var();
// Second function call
static_var();
?>
Output:
Static: 4
Non-static: 7
Static: 5
Non-static: 7
