Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.python > #100467 > unrolled thread

Re: subclassing collections.Counter

Back to article view | Back to comp.lang.python

This discussion starts older than the indexed window; earlier articles aren't shown. The article labeled Started by below is the oldest one visible, not the original post.

Contents

  Re: subclassing collections.Counter Peter Otten <__peter__@web.de> - 2015-12-15 17:08 +0100

#100467 — Re: subclassing collections.Counter

Pavlos Parissis wrote:

> I need to store values for metrics and return the average for some
> and the sum for the rest. Thus, I thought I could extend
> collections.Counter class by returning averages for some keys.
> 
> My class modifies the update() to increment a counter and the
> __getitem__ to perform the calculation. But, I get RuntimeError: maximum
> recursion depth exceeded as I access an attribute inside
> __getitem__.
> 
> Does anyone has an idea how I can achieve this?

> class CounterExt(Counter):

>     def __getitem__(self, key):
>         if (self.avg_metrics is not None and key in self.avg_metrics):
>             return self[key] / self._counter
>         else:
>             return self[key]

self[key] will call the CounterExt.__getitem__() method again. Use 
super().__getitem__(key) instead to invoke Counter.__getitem__().

[toc] | [standalone]

Back to top | Article view | comp.lang.python

csiph-web