Python Global Keyword

In Python, the global keyword is used to declare a variable in a function as a global variable. When a variable is declared as global within a function, it can be accessed and modified from outside the function as well.

Here's an example that demonstrates the use of the global keyword:

x = 10  # global variable

def foo():
    global x  # declare x as a global variable
    x = 20  # modify the global variable inside the function

foo()  # call the function
print(x)  # Output: 20 (global variable modified by the function)

In this example, we define a global variable x with a value of 10. We define a function foo() that modifies the global variable x using the global keyword. When we call the function and print the value of x, we can see that the global variable has been modified by the function.

It's important to note that if a variable is not declared as global within a function, Python will create a new local variable with the same name, which will shadow the global variable. Therefore, if you want to modify a global variable inside a function, you must use the global keyword to declare it as a global variable.