Enclosing scope in Python - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to print the value of the outer variable inside the inner function.

Python

def outer():
    x = 10
    def inner():
        print([1])
    inner()
outer()

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A10

Bx

Cinner

Douter

Attempts:

3 left

💡 Hint

Common Mistakes

Using the function name instead of the variable name.

Trying to print a variable not defined in the inner function.

The inner function can access the variable x from the enclosing scope.

2fill in blank

medium

Complete the code to modify the outer variable inside the inner function using the correct keyword.

Python

def outer():
    count = 0
    def inner():
        [1] count
        count += 1
        print(count)
    inner()
    inner()
outer()

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Anonlocal

Bglobal

Clocal

Douter

Attempts:

3 left

💡 Hint

Common Mistakes

Using global instead of nonlocal.

Not using any keyword and causing an error.

The nonlocal keyword allows the inner function to modify the variable count from the enclosing scope.

3fill in blank

hard

Fix the error in the code by completing the blank with the correct keyword to modify the outer variable.

Python

def counter():
    num = 5
    def increment():
        [1] num
        num += 2
        return num
    return increment()
print(counter())

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Alocal

Bouter

Cglobal

Dnonlocal

Attempts:

3 left

💡 Hint

Common Mistakes

Using global which causes an error here.

Not using any keyword causing an UnboundLocalError.

The nonlocal keyword is needed to modify num inside increment which is in the enclosing scope.

4fill in blank

hard

Fill both blanks to create a closure that remembers the value of start and adds step each time.

Python

def make_adder(start):
    step = 0
    def adder():
        nonlocal [1]
        [2] += 1
        return start + [2]
    return adder

add = make_adder(5)
print(add())
print(add())

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Astep

Bstart

Ccount

Dadder

Attempts:

3 left

💡 Hint

Common Mistakes

Using start instead of step.

Not declaring the variable as nonlocal.

The variable step should be declared nonlocal and incremented inside adder to remember its value.

5fill in blank

hard

Fill all three blanks to create a function that counts calls using an enclosing variable and returns the count.

Python

def call_counter():
    count = 0
    def counter():
        [1] count
        count [2] 1
        return [3]
    return counter

c = call_counter()
print(c())
print(c())

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Anonlocal

B+=

Ccount

Dglobal

Attempts:

3 left

💡 Hint

Common Mistakes

Using global instead of nonlocal.

Forgetting to return the updated count.

Use nonlocal to modify count, increment it with +=, and return count.