[Rd] simplify2array assumes non-NA dim() -- base or method bug?
Sebastian Meyer
@eb@meyer @end|ng |rom |@u@de
Thu Aug 25 11:55:24 CEST 2022
Hmm. I think I haven't seen NA dims in base R before. R-lang says
> The 'dim' attribute is used to implement arrays. The content of
> the array is stored in a vector in column-major order and the 'dim'
> attribute is a vector of integers specifying the respective extents of
> the array. R ensures that the length of the vector is the product of
> the lengths of the dimensions.
And R-intro says:
> A dimension vector is a vector of non-negative integers.
I understand "vector of [non-negative] integers" as excluding NA_integer_.
Correspondingly:
> a <- 1
> dim(a) <- NA_integer_
Error in dim(a) <- NA_integer_ : the dims contain missing values
> matrix(1, NA_integer_)
Error in matrix(1, NA_integer_) : invalid 'nrow' value (too large or NA)
> array(1, NA_integer_)
Error in array(1, NA_integer_) : negative length vectors are not allowed
There must be many more examples where non-NULL dim() is assumed to
not contain missing values.
simplify2array() aligns with that specification and only needs to check
for numeric (non-NULL) dims at this point and not also !anyNA(c.dim).
So my take is that there is no bug.
Best regards,
Sebastian Meyer
Am 25.08.22 um 04:51 schrieb Michael Chirico via R-devel:
> If any component of the dim() returned as c.dim here[1] are missing,
> simplify2array() errors inscrutably (specifically, because the last &&
> condition is missing):
>
> Error in if (higher && length(c.dim <- unique(lapply(x, dim))) == 1 && :
> missing value where TRUE/FALSE needed
>
> At root here is that dim.tbl_lazy ({dbplyr} package method [2]) very
> intentionally neglects to count the # of rows in the result -- the
> whole point of a lazy table is to avoid calculating full queries
> unless specifically requested, so the # of rows is left as missing,
> i.e., there _is_ a quantity of rows, but the exact number is not
> known.
>
> That seems to me like a proper usage of NA, and hence this is a
> simplify2array() bug, but I am curious other thoughts here before
> attempting a patch.
>
> [1] https://github.com/r-devel/r-svn/blob/2d4f8c283d53ff2c98d92c7b77b11e652297742c/src/library/base/R/sapply.R#L46-L48
> [2] https://github.com/tidyverse/dbplyr/blob/36b146e36d6d9af215dc48e60862d4b807b9e606/R/tbl-lazy.R#L45-L47
>
> ______________________________________________
> R-devel using r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel
More information about the R-devel
mailing list