PHP Variable Scope
In PHP there are three variable scope. They are : Local , Global and Static.
LOCAL VARIABLE : Local variable is the one which is declared within the function, has the local scope and can be accessed within the function only.
<!DOCTYPE html>
<html>
<body>
<?php
function demo() {
$x = 6; // local scope
echo "<p>Variable x inside function is: $x</p>";
}
demo();
// using x outside the function will generate an error
echo "<p>Variable x outside function is: $x</p>";
?>
</body>
</html>
GLOBAL VARIABLE : Global variable is the one which is declared outside the function and can be accessed from any function.
<?php
$x = 6; // global scope
function demo() {
// using x inside this function will generate an error
echo "<p>Variable x inside function is: $x</p>";
}
demo();
echo "<p>Variable x outside function is: $x</p>";
?>
You can use global keyword to access a global variable from within a function.
<?php
$x = 15;
$y = 10;
function demo() {
global $x, $y;
$y = $x + $y;
}
myTest();
echo $y; // output 25
?>
Use the global keyword before the variables (inside the function) as shown in above example.
STATIC VARIABLE : When a function is completed/executed, all of its variables are deleted. However, sometimes we want a local variable NOT to be deleted. For this static variable scope is declared.
<?php
function demo() {
static $x = 0;
echo $x;
$x++;
}
demo();
demo);
demo();
?>
You can use static keyword to access variable.
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