Re: Assigning to self

[Mark McEahern]

Frans Englich wrote:
Hello,
I am having trouble with throwing class instances around. Perhaps I'm 
approaching my goals with the wrong solution, but here's nevertheless a 
stripped down example which demonstrates my scenario:
 

[snip]
The basic problem seems to be that you're trying to avoid creating a new 
instance in __init__--which is too late.  By that point, the new object 
is already created.  Rebinding the name self in __init__ doesn't do what 
you seem to think it will.  Basically, you need to move the "only create 
this object if it doesn't already exist"  logic outside of __init__.

Here's an alternative approach:
#!/usr/bin/env python
class Item:
   def __init__(self, name):
       self.name = name
class Factory:
   items = {}
   def getItemByName(self, name):
       item = Factory.items.get(name)
       if not item:
           item = Item(name)
           Factory.items[name] = item
       return item
def main():
   factory = Factory()
   name = 'foo'
   for x in range(10):
       i = factory.getItemByName(name)
       print i
   print len(factory.items)
if __name__ == "__main__":
   main()
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