How do you define a global variable inside a function?

To define a global variable inside a function, the correct approach is to use the global keyword. This keyword informs the Python interpreter that you intend to use the variable declared in the global scope rather than creating a new local variable. When you declare a variable inside a function without the global keyword, Python treats it as a local variable by default, which means it will not affect the variable outside the function scope.

By using global, you can read and modify the global variable from within the function, effectively linking the function's variable to the outer scope's variable. This allows changes made to the variable in the function to persist after the function's execution completes.

The other methods, such as declaring the variable outside the function or using keywords like local or static, do not serve to define a global variable within a function context in the same way. Declaring outside the function does create a global variable, but does not pertain to how it is accessed or modified within the function itself. Therefore, understanding the specific role of the global keyword is essential for managing variable scope in Python effectively.