继续阅读sys.stdin

Question

Is it possible to continue reading input on sys.stdin ? I'm trying to continuously execute a function based on input. (My function only prints to sys.stdout and sys.stderr , and doesn't return anything.) My Code:

def prime(number):
    number = abs(int(number))
    for i in range(3, number):
        if number % i == 0:
            print("Not Prime!", file = sys.stderr, flush = True)
            sys.exit(0)
    print("Prime!", file = sys.stdout, flush = True)

for i in sys.stdin:
    prime(i)

Here's the output:

>>> for i in sys.stdin:
        prime(i)
43         # Input
Prime!     # In sys.stdout and it continues reading from sys.stdin
55         # Input
Not Prime! # In sys.stderr and stops.
>>>

I've tested it out and determined that it continues reading when the output of my function is on sys.stdout and stops when outputting on sys.stderr .

Answer 1

Well after you print 'Not prime' to sys.stderr you make a call to sys.exit which causes your program to terminate. If you remove this, reading on sys.stdin should continue until you issue an EOF character (Ctrl+Z on Windows, Ctrl+D on POSIX).