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

Groups > comp.lang.python > #6984

Re: except KeyError, everywhere

Show all headers | View raw

Wilbert Berendsen <wbsoft@xs4all.nl> writes:

> I find myself all over the place associating objects with each other using 
> dicts as caches:
>
> something like this:
>
> _cache = {}
>
> def get_something(obj):
>     """Returns the frobnicate-plugin for the specified object."""
>     try:
>         return _cache[obj]
>     except KeyError:
>         res = _cache[obj] = LargeClass(obj)
>         return res

You seem to be looking for the Memoize pattern
<URL:https://secure.wikimedia.org/wikipedia/en/wiki/Memoization>.

It's best to implement Memoize as a Python decorator in one place
<URL:http://wiki.python.org/moin/PythonDecoratorLibrary#Memoize>.

Once you have that decorator, apply it to any function you like::

    @memoized
    def get_something(obj):
        """ Returns the frobnicate-plugin for the specified object. """
        res = LargeClass(obj)
        return res

-- 
 \         “Faith may be defined briefly as an illogical belief in the |
  `\                  occurrence of the improbable.” —Henry L. Mencken |
_o__)                                                                  |
Ben Finney

Back to comp.lang.python | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

except KeyError, everywhere Wilbert Berendsen <wbsoft@xs4all.nl> - 2011-06-03 22:08 +0200
  Re: except KeyError, everywhere Nobody <nobody@nowhere.com> - 2011-06-04 01:02 +0100
    Re: except KeyError, everywhere --> memoization Wilbert Berendsen <wbsoft@xs4all.nl> - 2011-06-05 00:27 +0200
    Re: except KeyError, everywhere "Gabriel Genellina" <gagsl-py2@yahoo.com.ar> - 2011-06-07 00:45 -0300
      Re: except KeyError, everywhere Ben Finney <ben+python@benfinney.id.au> - 2011-06-07 14:08 +1000
  Re: except KeyError, everywhere Ben Finney <ben+python@benfinney.id.au> - 2011-06-04 10:03 +1000
    Re: except KeyError, everywhere Ben Finney <ben+python@benfinney.id.au> - 2011-06-04 10:37 +1000

csiph-web