Python Python List Comprehensions and Generators

Question 1

What is the output of `[x**2 for x in range(4)]`?

Accepted Answer

[0, 1, 4, 9]

Answer

[1, 4, 9, 16]

Answer

[0, 1, 2, 3]

Answer

[1, 2, 3, 4]

Question 2

Which syntax creates a generator expression in Python?

Accepted Answer

(x for x in range(10))

Answer

[x for x in range(10)]

Answer

{x for x in range(10)}

Answer

generator(x for x in range(10))

Question 3

What does the `yield` keyword do in a Python function?

Accepted Answer

Pauses execution and returns a value to the caller, resuming on next call

Answer

Returns a value and terminates the function

Answer

Raises a StopIteration exception

Answer

Creates a new thread

Question 4

What is the output of `list(x for x in range(5) if x % 2 == 0)`?

Accepted Answer

[0, 2, 4]

Answer

[1, 3]

Answer

[0, 1, 2, 3, 4]

Answer

[2, 4]

Question 5

Which of the following creates a set comprehension?

Accepted Answer

{x*2 for x in range(5)}

Answer

[x*2 for x in range(5)]

Answer

(x*2 for x in range(5))

Answer

set(x*2 for x in range(5) using {})

Question 6

What is the memory advantage of using a generator over a list?

Accepted Answer

Generators produce values one at a time, using constant memory

Answer

Generators store all values in memory upfront

Answer

Generators are faster for random access

Answer

Generators support indexing like lists