Multiple choice questions on lists and loops

Hi all,

here are a couple of multiple choice questions on lists. I had a bit of a hard time finding questions that only deal with a single subject. I’m also not completely sure that the possible “diagnosis” are the most accurate.

Let me know what you think!

Question 1 – Consider the following sequence of commands:

<br /> >>> list_a = ["a","b","c","d"]<br /> >>> list_b = []<br /> >>> while len(list_a) >= len(list_b) :<br /> >>> list_b.append(list_a.pop())<br />

What will the contents of both list_a and list_b be in the end of the while loop?

1. list_a = [“a”], list_b = [“d”, “c”, “b”] (Correct)
2. list_a = [“a”, “b”], list_b =[“d”, “c”] (Wrong – did not understand the while stopping condition)
3. list_a = [“a”, “b”, “c”, “d”], list_b = [“a”, “b”, “c”, “d”] (Wrong – does not understand pop?)
4. list_a = [“”], list_b = [“d”, “c”, “b”, “a”] (Wrong – did not understand the while stopping condition??)

**Question 2 – Consider the following sequence of commands: **
<br /> >>> list_a = ["a", "b", "c", "d"]<br /> >>> list_b = list_a<br /> >>> list_a.pop(len(list_b) -1);<br />
What will the output of the following command be?
<br /> print list_a.pop(len(list_b) -1)<br />

1. c (correct option)
2. d (Wrong answer – probably assuming that removed the item number 3 both times)
3. b (Wrong answer – recognising that len(list_b) is 3, but assuming that the array index starts from 1)
4. Python will return IndexError: pop index out of range (Wrong answer: probably assuming that len(list_b) is 4, when in fact it is 3)