Why doesn't print work in the console?

Question

Python

from nfstream import NFStreamer
import sys

path = sys.argv[1]
flow_streamer = NFStreamer(source=path)
result = {}

for flow in flow_streamer:
    print('-------------------------------------------------------------------------')
    print('FLOW')

output only when the program ends

Answer 1

Most likely the code is working correctly. Try putting a delay in your code, and convince yourself that print() outputs data to the console on each iteration of the loop:

from nfstream import NFStreamer
import sys
import time

path = sys.argv[1]
flow_streamer = NFStreamer(source=path)
result = {}

for flow in flow_streamer:
    print('-------------------------------------------------------------------------')
    print('FLOW')
    time.sleep(0.2)