Why does python use 'else' after for and while loops?

Question

I understand how this construct works:

for i in range(10):
    print(i)

    if i == 9:
        print(\"Too big - I\'m         


        

Answer 1

Here's another idiomatic use case besides searching. Let's say you wanted to wait for a condition to be true, e.g. a port to be open on a remote server, along with some timeout. Then you could utilize a while...else construct like so:

import socket
import time

sock = socket.socket()
timeout = time.time() + 15
while time.time() < timeout:
    if sock.connect_ex(('127.0.0.1', 80)) is 0:
        print('Port is open now!')
        break
    print('Still waiting...')
else:
    raise TimeoutError()