On Apr 20, 6:54 pm, Gerhard Häring <g...@ghaering.de> wrote: > Peter Otten wrote: > > bdb112 wrote: > > >> Your explanation of Boolean ops on lists was clear. > >> It leads to some intriguing results: > > >> bool([False]) > >> --> True > > >> I wonder if python 3 changes any of this? > > > No. Tests like > > > if items: > > ... > > > to verify that items is a non-empty list are a widespread idiom in Python. > > They rely on the behaviour you observe.
> Are they widespread? I haven't noticed, yet. > I prefer to write it explicitly: > if len(lst) > 0: > ... > if item is None: > ... > etc. Consider this snippet: while stack and some_condition(stack[-1]): # do stuff including popping and breaking else: # raise an exception Would you use an explicit len(stack) > 0 ? -- http://mail.python.org/mailman/listinfo/python-list
