如何在没有换行的情况下打印字符，在while循环内和睡眠中？

Question

I just realised, I can't print a character, on the same line with a delay.

import sys
import time
while True:
  sys.stdout.write('.')
  time.sleep(3.0)    

I can only see the result after I break the loop with CTRL+C . Is there a solution for that?

I would like to see each point being printed ..... , with a delay.

Answer 1

Output is probably buffered, it would eventually output to the terminal after the buffer was filled, but if you want it to be shown immediately you should explicitly flush output:

sys.stdout.flush()

in your loop

You can do this in one command in python 3:

print(".", end='', file=sys.stdout, flush=True) 

Answer 2

here is a sample how it can be done. print() has a parameter that can be set like: flush=True :

from time import sleep
count = 0
while count < 20:
    print('.', end='', flush=True) # prints all in one line
    #print('.', flush=True) # prints on separate lines
    sleep(1)
    count += 1