TIL: Python Print Buffer

Daniel — Fri, 24 Apr 2026 00:00:00 +0000

I was watching Miguel Grinberg’s talk on Pycon 2017 Asynchronous Python for the Complete Beginner last night. And tried a code snippet on my computer which is not really connected to the talk or async programming.

from time import sleep
def hello() -> None:
print("Hello", end=" ")
sleep(3)
print("World!")
if __name__ == "__main__":
hello()

What do you think will happen if we run the code? Terminal print’s Hello first, then after three seconds we see World! appear, right? Actually, no.

Python on Daniel's Blog

TIL: Python Print Buffer