LangWart: Method congestion from mutate multiplicty

Tim Chase python.list at
Sun Feb 10 14:52:35 CET 2013

On Sun, 10 Feb 2013 22:29:54 +1100, Steven D'Aprano wrote:
> Rick Johnson wrote:
> >  map, mapped
> >  filter, filtered
> >  reduce, reduced
> Those are nonsense. None of those are in-place mutator methods.
> Especially reduce, which reduces a list to a single item. You might
> as well have suggested "len, "lened".

And, if you want those in-place, indexing trivially comes to the
rescue again:

  lst[:] = map(transform_fn, lst)
  lst[:] = filter(check_fn, lst)

or, as I prefer:

  lst[:] = [transform_fn(x) for x in lst]
  lst[:] = [x for x in lst if check_fn(x)]

as they can be combined simply.


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