Oops, my bad. The utilities file I use gets loaded automatically when I start my interpreter, so I mistook isnumber for a built-in function. A battle-tested isnumber function is defined in Peter Norvig's utils.py (http://aima.cs.berkeley.edu/python/utils.py):
#def isnumber(x): # "Is x a number? We say it is if it has an __int__ method." # return hasattr(x, '__int__') Michael -- Michael D. Hartl, Ph.D. Chief Technology Officer http://quarksports.com/ -- http://mail.python.org/mailman/listinfo/python-list