[Numpy-discussion] New numpy functions: filled, filled_like

Robert Kern robert.kern@gmail....
Sun Jan 13 17:24:48 CST 2013

On Sun, Jan 13, 2013 at 6:27 PM, Nathaniel Smith <njs@pobox.com> wrote:
> Hi all,
> PR 2875 adds two new functions, that generalize zeros(), ones(),
> zeros_like(), ones_like(), by simply taking an arbitrary fill value:
>   https://github.com/numpy/numpy/pull/2875
> So
>   np.ones((10, 10))
> is the same as
>   np.filled((10, 10), 1)
> The implementations are trivial, but the API seems useful because it
> provides an idiomatic way of efficiently creating an array full of
> inf, or nan, or None, whatever funny value you need. All the
> alternatives are either inefficient (np.ones(...) * np.inf) or
> cumbersome (a = np.empty(...); a.fill(...)). Or so it seems to me. But
> there's a question of taste here; one could argue instead that these
> just add more clutter to the numpy namespace. So, before we merge,
> anyone want to chime in?

One alternative that does not expand the API with two-liners is to let
the ndarray.fill() method return self:

  a = np.empty(...).fill(20.0)

Robert Kern

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