Global keyword in Python - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the global keyword do in Python?

The global keyword tells Python that a variable inside a function refers to the variable defined outside the function, at the global level. It allows you to change the global variable from inside the function.

beginner

Why do you need the global keyword to modify a global variable inside a function?

Without global, Python treats variables assigned inside a function as local. Using global tells Python to use the variable from outside the function, so changes affect the global variable.

beginner

What happens if you try to modify a global variable inside a function without using global?

Python creates a new local variable with the same name inside the function. The global variable remains unchanged outside the function.

beginner

Show a simple example of using global to change a global variable inside a function.

Example:

count = 0

def increment():
    global count
    count += 1

increment()
print(count)  # Output: 1

intermediate

Can the global keyword be used to create a new global variable inside a function?

Yes. If the global variable does not exist yet, using global inside a function and assigning a value will create it at the global level.

What does the global keyword do inside a function?

A Allows modifying a variable defined outside the function

B Creates a new local variable

C Deletes a global variable

D Imports a module globally

The global keyword lets you modify a variable defined outside the function.

What happens if you assign a value to a variable inside a function without using global?

A The variable becomes read-only

B The global variable is changed

C Python throws an error

D A new local variable is created

Without global, assignment creates a new local variable.

Which keyword do you use to tell Python to use the global variable inside a function?

A local

B extern

C global

D nonlocal

The global keyword is used to access and modify global variables.

Can you create a new global variable inside a function using global?

A Yes, by declaring it global and assigning a value

B No, global variables must be defined outside functions

C Only if the variable name starts with 'g_'

D Only in Python 2

Using global and assigning a value inside a function creates a new global variable.

What will this code print?

count = 5
def change():
    count = 10
change()
print(count)

A 10

B 5

C Error

D None

Without global, count = 10 creates a local variable. The global count stays 5.

Explain how the global keyword affects variable scope inside a function.

Think about how Python treats variables inside functions by default.

Describe a situation where you would need to use the global keyword in your code.

Consider when a function needs to update a value defined outside it.