enumerate() function in Python - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the enumerate() function do in Python?

It adds a counter to an iterable (like a list) and returns it as an enumerate object, which yields pairs of (index, item).

beginner

How do you use enumerate() with a list fruits = ['apple', 'banana', 'cherry'] to get index and fruit?

Use a for loop:
for index, fruit in enumerate(fruits):
print(index, fruit)

intermediate

What is the purpose of the optional start parameter in enumerate()?

It sets the starting index number. By default, it starts at 0, but you can change it to any integer.

intermediate

What type of object does enumerate() return?

It returns an enumerate object, which is an iterator that produces pairs of (index, item) when looped over.

beginner

Why is enumerate() better than using a manual counter variable in a loop?

Because it is cleaner, less error-prone, and makes the code easier to read by automatically handling the index counting.

What does enumerate(['a', 'b', 'c']) produce when converted to a list?

A [(1, 'a'), (2, 'b'), (3, 'c')]

B ['a', 'b', 'c']

C [(0, 'a'), (1, 'b'), (2, 'c')]

D ['0a', '1b', '2c']

The default start index is 0, so enumerate pairs each item with its index starting at 0.

How can you start enumeration at 1 instead of 0?

A enumerate(iterable, start=1)

B enumerate(iterable, 1)

C enumerate(iterable).start(1)

D enumerate(iterable).index(1)

The start parameter sets the starting index, so use enumerate(iterable, start=1).

Which of these is a correct way to get index and value from a list nums?

A for i in enumerate(nums): val = i

B for i, val in enumerate(nums):

C for val, i in enumerate(nums):

D for i in nums.enumerate():

The enumerate function returns (index, value) pairs, so unpack as i, val.

What type of object is returned by enumerate()?

A Enumerate object (iterator)

B Tuple

C Dictionary

D List

enumerate() returns an iterator object that yields index-item pairs.

Why might you prefer enumerate() over a manual counter variable?

A It automatically handles counting and is less error-prone.

B It runs faster than any loop.

C It creates a dictionary automatically.

D It sorts the list while looping.

enumerate() simplifies code by managing the index count automatically.

Explain how the enumerate() function works and give an example of its use.

Think about how you get both position and value when looping.

Describe the purpose of the start parameter in enumerate() and how to use it.

It lets you choose where counting begins.