Bruno Desthuilliers wrote: > Diez B. Roggisch a écrit : >> momobear schrieb: >>> hi, I am puzzled about how to determine whether an object is >>> initilized in one class, anyone could give me any instructions? >>> here is an example code: >>> >>> class coffee: >>> def boil(self): >>> self.temp = 80 >>> >>> a = coffer() >>> if a.temp > 60: >>> print "it's boiled" >>> >>> in C++ language we must initilized a variable first, so there is no >>> such problem, but in python if we don't invoke a.boil(), we will not >>> get self.temp to be initilized, any way to determine if it's initilzed >>> before self.temp be used. >> You want boil to be called __init__, which is python's constructor name. > > <nitpicking> > Actually, __init__ is the initializer. The proper constructor is __new__. > </nitpicking> > <nitpicking severity="be-kind-to-novices"> Actually you would have to ensure that the class's metaclass was <type "type"> for that to be true. Classic classes don't *have* a __new__ method. </nitpicking>
And of course the real answer is that the __init__ method should set a default value (modulo the sneaky use of class attributes) for any attributes that might be accessed before other methods get a chance to set them. regards Steve -- Steve Holden +44 150 684 7255 +1 800 494 3119 Holden Web LLC/Ltd http://www.holdenweb.com Skype: holdenweb http://del.icio.us/steve.holden Recent Ramblings http://holdenweb.blogspot.com -- http://mail.python.org/mailman/listinfo/python-list
