[Numpy-discussion] Indexing empty dimensions with empty arrays

Jordi Gutiérrez Hermoso jordigh at octave.org
Wed Dec 28 09:46:27 EST 2011


On 28 December 2011 03:33, Ralf Gommers <ralf.gommers at googlemail.com> wrote:
>
>
> 2011/12/27 Jordi Gutiérrez Hermoso <jordigh at octave.org>
>>
>> On 26 December 2011 14:56, Ralf Gommers <ralf.gommers at googlemail.com>
>> wrote:
>> >
>> >
>> > On Mon, Dec 26, 2011 at 8:50 PM, <josef.pktd at gmail.com> wrote:
>> >> I have a hard time thinking through empty 2-dim arrays, and don't know
>> >> what rules should apply.
>> >> However, in my code I might want to catch these cases rather early
>> >> than late and then having to work my way backwards to find out where
>> >> the content disappeared.
>> >
>> >
>> > Same here. Almost always, my empty arrays are either due to bugs or they
>> > signal that I do need to special-case something. Silent passing through
>> > of
>> > empty arrays to all numpy functions is not what I would want.
>>
>> I find it quite annoying to treat the empty set with special
>> deference. "All of my great-grandkids live in Antarctica" should be
>> true for me (I'm only 30 years old). If you decide that is not true
>> for me, it leads to a bunch of other logical annoyances up there
>
>
> Guess you don't mean true/false, because it's neither. But I understand you
> want an empty array back instead of an error.

It should be true. This is a case of vacuous truth:

    http://en.wikipedia.org/wiki/Vacuous_truth

- Jordi G. H.



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