[Rd] Is this a bug in `[`?

[Iñaki Úcar]

El sáb., 4 ago. 2018 a las 15:32, Rui Barradas
(<ruipbarradas using sapo.pt>) escribió:
>
> Hello,
>
> Maybe I am not understanding how negative indexing works but
>
> 1) This is right.
>
> (1:10)[-1]
> #[1]  2  3  4  5  6  7  8  9 10
>
> 2) Are these right? They are at least surprising to me.
>
> (1:10)[-0]
> #integer(0)
>
> (1:10)[-seq_len(0)]
> #integer(0)
>
>
> It was the last example that made me ask, seq_len(0) whould avoid an
> if/else or something similar.

I think it's ok, because there is no negative zero integer, so -0 is 0.

1.0/-0L # Inf
1.0/-0.0 # - Inf

And the same can be said for integer(0), which is the result of
seq_len(0): there is no negative empty integer.

Iñaki

>
>
> Thanks in advance,
>
> Rui Barradas
>
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