生成器和列表理解输入

Question

My intention is to input 2 lists one after the other after hitting enter on the input, when I run the following line I don't get any input and no error on jupyter.

N = (list(map(int,input().split())) for _ in range(2))

But when I build a list of lists which is not my intention it works and input is provided.

N = [list(map(int,input().split())) for _ in range(2)]

I clearly don't understand what is going on here.

Answer 1

in your first line you gave a generator expression , this will be executed if you iterate over, you could use

next(N)

or

list(N)

in your second line, you have a list comprehension that will execute your code immediately

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My intention is to input 2 lists one after the other after hitting enter on the input

as far as I understand you want to get 2 lists from 1 input, for this you will need to have a separator between lists:

sep = '|'
[list(map(int, l.split())) for l in input().split(sep)]
# input: 1 2 3| 0 4 9

output:

[[1, 2, 3], [0, 4, 9]]

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also, you can unpack the result in 2 lists after you "grab" and process the input:

list1, list2  = [list(map(int,input().split())) for _ in range(2)]