9.4. List operations¶

The + operator concatenates lists:

Similarly, the * operator repeats a list a given number of times:

The first example repeats four times. The second example repeats the list three times.

Q-3: What is printed by the following statements?

alist = [4, 2, 8, 6, 5]
alist = alist + 999
print(alist)

[4, 2, 8, 6, 5, 999]
You cannot concatenate a list with an integer.
Error, you cannot concatenate a list with an integer.
Yes, in order to perform concatenation you would need to write alist+[999]. You must have two lists.
[[4, 2, 8, 6, 5], 999]
You cannot concatenate a list with an integer. This would cause an error, not create a new list.
[4, 2, 8, 6, 5]
This will cause an error, but alist will remain unchanged.

Q-4: What is printed by the following statements?

alist = [1, 3, 5]
blist = [2, 4, 6]
print(alist + blist)

6
Concatenation does not add the lengths of the lists.
[1, 2, 3, 4, 5, 6]
Concatenation does not reorder the items.
[1, 3, 5, 2, 4, 6]
Yes, a new list with all the items of the first list followed by all those from the second.
[3, 7, 11]
Concatenation does not add the individual items.

Q-5: What is printed by the following statements?

alist = [1, 3, 5]
print(alist * 3)