HI! I'm using the idiom a = a or b to get rid of statements like if a is None: a = b Now I wonder what happens if both a and b have zero-length values. Trying in Python 2.2.1 reveals: >>> repr(0 or None) 'None' >>> repr(None or 0) '0' >>> repr('' or None) 'None' >>> repr(None or '') "''" >>> Is it guaranteed to work like this or should that be avoided? Ciao, Michael.