Python garbage collection

Question

I have created some python code which creates an object in a loop, and in every iteration overwrites this object with a new one of the same type. This is done 10.000 times,

Answer 1

This is an old error that was corrected for some types in python 2.5. What was happening was that python was not so good at collecting things like empty lists/dictionaries/tupes/floats/ints. In python 2.5 this was fixed...mostly. However floats and ints are singletons for comparisons so once one of those is created it stays around as long as the interpreter is alive. I've been bitten by this worst when dealing with large amount of floats since they have a nasty habit of being unique. This was characterized for python 2.4 and updated about it being folded into python 2.5

The best way I've found around it is to upgrade to python 2.5 or newer to take care of the lists/dictionaries/tuples issue. For numbers the only solution is to not let large amounts of numbers get into python. I've done it with my own wrapper to a c++ object, but I have the impression that numpy.array will give similar results.

As a post script I have no idea what has happened to this in python 3, but I'm suspicious that numbers are still part of a singleton. So the memory leak is actually a feature of the language.