[Python-Dev] PEP 8 update (original) (raw)

Guido van Rossum guido at python.org
Tue Apr 7 21:31:49 CEST 2015

Talk about hijacking an unrelated thread... :-(

Though there's maybe a style rule for the ternary operator to be devised here? :-) On Apr 7, 2015 11:36 AM, "Stefan Behnel" <stefan_ml at behnel.de> wrote:

Antoine Pitrou schrieb am 07.04.2015 um 14:26: > On Tue, 07 Apr 2015 03:11:30 +0100 > Rob Cliffe <rob.cliffe at btinternet.com> wrote: >> >> On 07/04/2015 02:08, Guido van Rossum wrote: >>> I've taken the liberty of adding the following old but good rule to >>> PEP 8 (I was surprised to find it wasn't already there since I've >>> lived by this for ages): >>> >>> * >>> >>> Be consistent in return statements. Either all return statements >>> in a function should return an expression, or none of them should. >>> If any return statement returns an expression, any return >>> statements where no value is returned should explicitly state this >>> asreturn None, and an explicit return statement should be present >>> at the end of the function (if reachable). >>> >>> Yes: >>> >>> def foo(x): >>> if x >= 0: >>> return math.sqrt(x) >>> else: >>> return None >>> >> That would seem to be good style and common sense. >> >> As a matter of interest, how far away from mainstream am I in >> preferring, in this particular example (obviously it might be >> different for more complicated computation), >> >> def foo(x): >> return math.sqrt(x) if x >= 0 else None > > I agree with you on this.

+1, the ternary operator reads best when there is a "normal" case that can go first and a "special" or "unusual" case that can go last and does not apply under the (given) normal conditions. Stefan

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