Problem when reading values from console using stdin.read()

Question

I have this part of python code that should read input values from the screen. When it runs, it keeps running forever. I tried CTRL+D as per the search results, but it does not work. This code is given and it works when I submit the code to an online grader but does not work on my windows machine.

if __name__ == "__main__":
    data = list(map(int, sys.stdin.read().split()))
    n, capacity = data[0:2]
    values = data[2:(2 * n + 2):2]
    weights = data[3:(2 * n + 2):2]

    opt_value = get_optimal_value(capacity, weights, values)

    print("{:.10f}".format(opt_value))

Sample input should be:

input() accepts one line only. I should be able to submit multiple lines — MSaudi, Sep 28 '21 at 14:15
@Virtuoz it works if I, instead of inserting multiple lines, I add all the inputs in single line. — MSaudi, Sep 28 '21 at 14:18
@jarmod it seems so. They probably using input files for running the tests and I should either do that or use Vittuoz suggestion — MSaudi, Sep 28 '21 at 14:25
The input's coming from the keyboard, a pipe, or stdin redirection, presumably. Not actually from the screen. — jarmod, Sep 28 '21 at 14:28
On Windows it's Ctrl-Z instead of Ctrl-D, and it should be the first character of the line (and followed by an enter). So on Windows, try: Enter + Ctrl-Z + Enter. This wil result in only one newline in the result. — wovano, Sep 28 '21 at 14:34
@wovano, that's it, man. It should be exactly like you said. I tried it and it works. — MSaudi, Sep 29 '21 at 12:32
@wovano You may post that as an answer, and I will accept it. — MSaudi, Sep 29 '21 at 12:46

score 0 · Accepted Answer · answered Sep 29 '21 at 18:30

On Windows you should use Ctrl-Z instead of Ctrl-D. Also, this should be the first character of a newline, and there should be a newline (enter) after the Ctrl-Z as well. There may be other characters after the Ctrl-Z, which will be ignored.

So, the shortest sequence to force an EOL on Windows is: Enter, Ctrl-Z, Enter.

I know this from experience and did found some answers or comments stating the same, but I couldn't find any official documentation where this is explained. If I find it, I will add it to this answer.

_{(please leave a comment if you know a reliable source for this behaviour.)}

Problem when reading values from console using stdin.read()

1 Answers1