Safely add a key to a dict only if it does not already exist?
Vito De Tullio
vito.detullio at gmail.com
Sat Jan 19 02:25:27 EST 2013
Steven D'Aprano wrote:
> I wish to add a key to a dict only if it doesn't already exist, but do it
> in a thread-safe manner.
>
> The naive code is:
>
> if key not in dict:
> dict[key] = value
>
>
> but of course there is a race condition there: it is possible that
> another thread may have added the same key between the check and the
> store.
>
> How can I add a key in a thread-safe manner?
using locks?
import threading
lock = threading.Lock()
with lock:
if key not in dict:
dict[key] = value
--
ZeD
More information about the Python-list
mailing list