Op 2005-12-12, Fredrik Lundh schreef <[EMAIL PROTECTED]>: > Pierre Quentel wrote: > >> In some program I was testing if a variable was a boolean, with this >> test : if v in [True,False] >> >> My script didn't work in some cases and I eventually found that for v = >> 0 the test returned True >> >> So I changed my test for the obvious "if type(v) is bool", but I still >> find it confusing that "0 in [True,False]" returns True >> >> By the way, I searched in the documentation what "obj in list" meant and >> couldn't find a precise definition (does it test for equality or >> identity with one of the values in list ? equality, it seems) ; did I >> miss something ? > >>>> issubclass(bool, int) > True >>>> isinstance(False, int) > True >>>> False == 0 > True >>>> int(False) > 0 > > but seriously, unless you're writing an introspection tool, testing for > bool is pretty silly. just use "if v" or "if not v", and leave the rest to > Python.
That depends on the circumstances. I have code where a particular variable can be a boolean or an integer. I don't want that code to behave the same on 0 and False nor on any other number and True. -- Antoon Pardon -- http://mail.python.org/mailman/listinfo/python-list
