On 9/25/08, Kent Johnson <[EMAIL PROTECTED]> wrote: > On Thu, Sep 25, 2008 at 4:24 AM, Steve Collins <[EMAIL PROTECTED]> > wrote: > >> However, some of the instances refer explicitly to other instances >> instances. It's obvious why this causes problems. It occurred to me to >> simply replace the instances with the ones in the un-pickled list, but I >> don't know how. > >> I tried using the following approach: >> >> class Z: >> def __init__(self,y): >> self.y = y >> def replaceZ (self,withWhat): >> self = withWhat > > 'self' is just another parameter passed to the method, so this just > rebinds a local name. >
That makes sense. At least I understand why it doesn't work now. > This example doesn't seem to illustrate the situation you describe. > You can replace the 'y' attribute of a Z object by assigning to it. > > One solution might be to make all your objects pickleable. Pickle > tracks object references and handles embedded references correctly. > >> That doesn't raise any errors, but it also doesn't work: >> >>>>> a = X(10) >>>>> b = X(20) > > Presumably this should be Z(10), Z(20) ? >>>>> print a.y >> 10 >>>>> print b.y >> 20 >>>>> b.replaceZ(a) >>>>> print b.y >> 20 > > If you want 'b' to refer to the same thing as 'a', just assign > b = a that's what I was trying (incorrectly) to achieve the above example. but how can I do this for an arbitrary number of objects in a list? I have a list x = [a,b,c] and a list y = [d,e,f], both filled with instance objects. I want the instance at x[n] to reference the instance at y[n] n = 0 while n < range(len(x)) x[n] = y[n] n+=1 given the contents of your link, I understand why x == [d,e,f] and not a == d etc., but how can I make a == d by iterating through two lists? > > I think you have some common misconceptions about the nature of > variables and assignment in Python. This may help: > http://personalpages.tds.net/~kent37/kk/00012.html > > Kent > I should note that I am very much a novice programmer, and really appreciate the feedback. Thanks, Steve _______________________________________________ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
