On Mon, Apr 20, 2009 at 1:54 AM, 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:
Nope, that's not idiomatic. The simpler `if lst:` version is indeed widespread. > ... > > if item is None: That's pretty common and accepted; comparison to None is something of a special case. Cheers, Chris -- I have a blog: http://blog.rebertia.com -- http://mail.python.org/mailman/listinfo/python-list
