1.23. Tuples and Lists

Tuples are useful to keep the data and prevent any changes on them. Lists on the other hand are mutable and enable changes on the data. As you may already know, both types can be heterogenous. In other words, the data contained by these types do not have to be in the same type.

In this example question, you will observe the properties of these types and how we can exploit them.

Suppose you’re given a tuple by the user, in the first input line. This tuple should contain only integers. The user has forgotten one of them and used a "?" string in place of it. After remembering the value of this integer, in the second line of the input he enters a two-tuple. The first number is the index of the "?" and the second is the integer value that is going to be substituted in place of "?" .

You are expected to fix the original tuple with this later information and print the corrected tuple.

Sample I/O:

Input:
(1,2,3,"?",5)
(3,4)

Output:
(1,2,3,4,5)

Input:
(1,3,5,7,12,14,"?",40)
(6,17)

Output:
(1,3,5,7,12,14,17,40)

Show the Answer

original_tuple = eval(input())          # *see below for explanation
index, missing_number = eval(input())   # notice tuple matching

lst = list(original_tuple)              # cast tuple to list so that you can change
lst[index] = missing_number

recovered_tuple = tuple(lst)            # cast list back to tuple again.

print(recovered_tuple)

"""*This is a tricky way to get a tuple or a list from the user.
It's not very safe but it is easy to do so for now.
You will learn the more proper way to this later."""