Would it be stupid to recode `dim` to return `length` if `dim(x)==NULL`?

Question

As pointed out in this question and copious official & unofficial R documentation,

x <- complex(15)
dim(x) == NULL

For me it's annoying to have to write a separate method (or if clause) for atomic vectors rather than being able to use dim(x)[1]. Would it be stupid to recode dim (a primitive) so it automatically returns length if dim(x)==NULL?

To be a bit more concrete: Are popular packages going to break if I recode dim in let's say my .Rprofile? Is this stupid for another reason I'm not seeing?

Do you see any downside to just calling the more general function something like `Dim`, as in `Dim <- function(x) {if(is.vector(x)) length(x) else dim(x)}`? — Josh O'Brien, Sep 06 '14 at 06:38
See `NROW` and `NCOL` for functions to return extents in a dimension-agnostic way. — Hong Ooi, Sep 06 '14 at 07:35
@HongOoi They work of course but still require me to write extra code for something which seemingly shouldn't be so obtuse. — isomorphismes, Sep 06 '14 at 07:43

score 4 · Accepted Answer · answered Sep 06 '14 at 10:13

4

It's unclear what you're trying to do, but the NROW and NCOL functions are ways to retrieve extents in a dimension-agnostic way. They treat vectors as column vectors, so NROW(X) is the same as length(x) and NCOL(x) is 1 when x is a vector.

> x <- numeric(10) # or complex, character, logical, etc
> nrow(x)
NULL
> NROW(x)
[1] 10
> NCOL(x)
[1] 1

> m <- matrix(1:10, nrow=5)
> nrow(m)
[1] 5
> NROW(m)
[1] 5
> NCOL(m)
[1] 2

answered Sep 06 '14 at 10:13

Hong Ooi

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Thanks @Hong Ooi. I didn't realise in comments that capitalisation mattered. – isomorphismes Sep 06 '14 at 22:59
This answer is good, but the other question is much better. That is why I switched the duplicates. – Matthew Lundberg Oct 22 '14 at 04:47
Or, at least, the other question is more likely to get google hits. – isomorphismes Oct 22 '14 at 05:15

Would it be stupid to recode `dim` to return `length` if `dim(x)==NULL`?

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