On 08.05.2015 14:04, Dave Angel wrote: > It might be appropriate to define the list at top-level, as > > EMPTY_LIST=[] > > and in your default argument as > def x(y, z=EMPTY_LIST): > > and with the all-caps, you're thereby promising that nobody will modify > that list. > > (I'd tend to do the None trick, but I think this alternative would be > acceptable)
I think it's a really bad idea to use a module-global mutable "EMPTY_LIST". It's much too easy this happens: # Globally >>> EMPTY_LIST = [ ] # At somewhere in the code at some point in time >>> foo = EMPTY_LIST >>> foo.append(123) >>> print(foo) [123] # Some other place in code >>> bar = EMPTY_LIST >>> print(bar) [123] Regards, Johannes -- >> Wo hattest Du das Beben nochmal GENAU vorhergesagt? > Zumindest nicht öffentlich! Ah, der neueste und bis heute genialste Streich unsere großen Kosmologen: Die Geheim-Vorhersage. - Karl Kaos über Rüdiger Thomas in dsa <hidbv3$om2$1...@speranza.aioe.org> -- https://mail.python.org/mailman/listinfo/python-list
