Thank you everyone. I, indeed, found it in your book, Wes, after I knew it was something extra special.
The explanations here are great! Thank you everyone. Marilyn On Sun, 13 May 2007, wesley chun wrote: > > I'm stumped. This silly bit of code doesn't work. I expect the > > output to be 8, not 18. What am I missing? > > > > class Under10(int): > > def __init__(self, number): > > number %= 10 > > int.__init__(self, number) > > marilyn, > > i agree with most of the earlier replies... you need to use __new__() > instead of __init__() in order to "tweak" the original value before > the instance of the immutable object is created. once it's "frozen," > you're stuck. note that __new__() is a class method, so you'll need a > variable for the class (instead of self for the instance). > > also recall that __init__() is (the 1st method) called *after* an > instance has been created, which for you, would be too late. in > practice, i don't think __init__() is ever used for deriving from > immutable types. does anyone have a counterexample? > > (since i know you've been reading Core Python, you can take a look at > my example of subclassing an immutable type on p.552.) :-) > > cheers, > -- wesley > - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - > "Core Python Programming", Prentice Hall, (c)2007,2001 > http://corepython.com > > wesley.j.chun :: wescpy-at-gmail.com > python training and technical consulting > cyberweb.consulting : silicon valley, ca > http://cyberwebconsulting.com > -- _______________________________________________ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
