mcl wrote: > On 7 Jul, 13:09, Jeff <[EMAIL PROTECTED]> wrote: >> When you call c3.createJoe(c1.fred), you are passing a copy of the >> value stored in c1.fred to your function. Python passes function >> parameters by value. The function will not destructively modify its >> arguments; you must expliticly state your intention to modify an >> object: >> >> class one(): >> fred = 'fred' >> >> class three(): >> def createJoe(self, myName): >> return "Joe" >> >> def main(): >> c1 = one() >> c3 = three() >> c1.fred = c3.createJoe() # Modify c1's attribute, fred, with the >> return value from c3.createJoe > > Thank you very much for your helpful replies. > > Two questions: > One: > My use of classes is because I want two classes one for global > variables and one for global functions.
That's odd. Usually, you shouldn't be using any globals at all. Callers should use their own local variables, or instances or whatever. > A function may set multiple global variable values, so what is the > best way to do this as 'return' only appears to be able to set one > value. You can return a tuple, and then use tuple unpacking. >>> def f(): ... return 1, 2 >>> one, two = f() >>> one 1 >>> two 2 > Two: > I am sorry but I do not understand the significance defining a Class > as: > >>> class MyClass(object): > what is object ? > > I am using python with Google App Engine, and I only have Alex > Martelli's book up to Python 2.2, if they has any relevance ? By inheriting from object, your class becomes a new-style class. Otherwise, it's old-style. Honestly, I don't know all of the differences, but new-style classes are better. For one thing, old-style classes don't support properties or super(). They were introduced in Python 2.2. Your Python 2.2 book probably centers around old-style classes. > Thanks again for your help. I now understand what my mistakes were and > why I was not getting the results I had expected. > > Richard -- -- http://mail.python.org/mailman/listinfo/python-list
