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

Olivier Delalleau shish@keba...
Thu Jan 17 19:01:26 CST 2013


2013/1/17 Matthew Brett <matthew.brett@gmail.com>:
> Hi,
>
> On Thu, Jan 17, 2013 at 10:27 PM, Mark Wiebe <mwwiebe@gmail.com> wrote:
>>
>> On Thu, Jan 17, 2013 at 2:10 PM, Benjamin Root <ben.root@ou.edu> wrote:
>>>
>>>
>>>
>>> On Thu, Jan 17, 2013 at 5:04 PM, Eric Firing <efiring@hawaii.edu> wrote:
>>>>
>>>> On 2013/01/17 4:13 AM, Pierre Haessig wrote:
>>>> > Hi,
>>>> >
>>>> > Le 14/01/2013 20:05, Benjamin Root a écrit :
>>>> >> I do like the way you are thinking in terms of the broadcasting
>>>> >> semantics, but I wonder if that is a bit awkward.  What I mean is, if
>>>> >> one were to use broadcasting semantics for creating an array, wouldn't
>>>> >> one have just simply used broadcasting anyway?  The point of
>>>> >> broadcasting is to _avoid_ the creation of unneeded arrays.  But maybe
>>>> >> I can be convinced with some examples.
>>>> >
>>>> > I feel that one of the point of the discussion is : although a new (or
>>>> > not so new...) function to create a filled array would be more elegant
>>>> > than the existing pair of functions "np.zeros" and "np.ones", there are
>>>> > maybe not so many usecases for filled arrays *other than zeros values*.
>>>> >
>>>> > I can remember having initialized a non-zero array *some months ago*.
>>>> > For the anecdote it was a vector of discretized vehicule speed values
>>>> > which I wanted to be initialized with a predefined mean speed value
>>>> > prior to some optimization. In that usecase, I really didn't care about
>>>> > the performance of this initialization step.
>>>> >
>>>> > So my overall feeling after this thread is
>>>> >   - *yes* a single dedicated fill/init/someverb function would give a
>>>> > slightly better API,
>>>> >   -  but *no* it's not important because np.empty and np.zeros covers
>>>> > 95
>>>> > % usecases !
>>>>
>>>> I agree with your summary and conclusion.
>>>>
>>>> Eric
>>>>
>>>
>>> Can we at least have a np.nans() and np.infs() functions?  This should
>>> cover an additional 4% of use-cases.
>>>
>>> Ben Root
>>>
>>> P.S. - I know they aren't verbs...
>>
>>
>> Would it be too weird or clumsy to extend the empty and empty_like functions
>> to do the filling?
>>
>> np.empty((10, 10), fill=np.nan)
>> np.empty_like(my_arr, fill=np.nan)
>
> That sounds like a good idea to me.  Someone wanting a fast way to
> fill an array will probably check out the 'empty' docstring first.
>
> See you,
>
> Matthew

+1 from me. Even though it *is* weird to have both "empty" and "fill" ;)

-=- Olivier


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