Giampaolo Rodolà wrote:
Il 21 gennaio 2012 22:13, Erik Max Francis <m...@alcyone.com> ha scritto:
The real reason people still use the `while 1` construct, I would imagine,
is just inertia or habit, rather than a conscious, defensive decision. If
it's the latter, it's a case of being _way_ too defensive.
It's also because while 1 is faster:
...
while True: 1.41121292114
while 1: 1.07101011276
Most of the times tha't won't make any noticeable difference, but it's
also true that certain while loops are going to iterate milions of
times.
Think about receiving a 10 GB file by using a socket. You'd tipically
have something like this:
while 1:
chunk = sock.recv(1024):
if not chunk:
break
...
Now, that's a case where I (personally) want to explicitly use "while
1" instead of "while True".
Such a loop would obviously be I/O-bound, not CPU-bound. So changing
the form of the while loop would make minimal difference to its overall
performance. It'd be spending the vast majority of its time blocked at
the OS socket level, not executing the condition of the while loop.
As with most of these things, if one is this worried about performance,
then either Python was the wrong choice to begin with, or there's a good
chance that you're worried about something that isn't actually where the
bottleneck is in the first place.
--
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