How to read multiple lists from STDIN in python?

Question

I am newbie to python and trying to understand itertools.product. I am unable to read multiple lists from input.

Initially I have given manual input like below.

list1 = [1,2]
list2 = [3,4]
print(*product(list1, list2))

and got output as (1, 3) (1, 4) (2, 3) (2, 4), which is perfectly fine.

I wanted the same thing for multiple lists to be used in product function.

I have tried like below

TotList = product(list(map(int,input().split())) for _ in range(2)) #in range function 2 can be vary
for item in TotList:
    print(*item)

But it is not working like a product tool

Current input:

1 2
3 4

Output:

[1, 2]
[3, 4]

Expected output:

(1, 3) (1, 4) (2, 3) (2, 4)

So your expected output is an unbound collection of tuples? If that's the case, then calling the list constructor in TotList will always override. What exactly is the output you want and why? That will help get you an answer. — Sam
– Sam, Commented Aug 5, 2019 at 19:07
I am trying to solve the problem available at hackerrank.com/challenges/maximize-it/problem. below answer by Sunitha helped me to solve the issue. — San
– San, Commented Aug 6, 2019 at 15:29

Sunitha · Accepted Answer · 2019-08-05 19:06:55Z

3

You have to specify * operator to unpack the iterables produced by map and feed it to product

>>> TotList = product(*(map(int,input().split()) for _ in range(2)))
1 2
3 4
>>> for item in TotList:
...     print(*item)
... 
1 3
1 4
2 3
2 4
>>>

answered Aug 5, 2019 at 19:06

Sunitha

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