R devel - Dec 2025 - which.max does not work on numeric_version class vectors

versions <- c("9.10", "9.2")
  nv <- numeric_version(versions)
  class(nv)
  ## [1] "numeric_version"

  max(nv) # ok
  ## [1] ?9.10?

  versions[tail(order(nv), 1)] # ok
  ## [1] "9.10"

  sort(nv, decreasing = TRUE)[1] # ok
  ## [1] ?9.10?

  versions[which.max(xtfrm(nv))] # ok
  ## [1] "9.10"

  versions[which.max(nv)] # error
  ## Error in which.max(nv) : 'list' object cannot be coerced to type
'double'


-- 
Statistics & Software Consulting
GKX Group, GKX Associates Inc.
tel: 1-877-GKX-GROUP
email: ggrothendieck at gmail.com

Are objects of class 'numeric_version' of class 'numeric' ?


I guess that is the problem...


Best

F.

On 12/20/25 16:34, Gabor Grothendieck wrote:
>    versions <- c("9.10", "9.2")
>    nv <- numeric_version(versions)
>    class(nv)
>    ## [1] "numeric_version"
>
>    max(nv) # ok
>    ## [1] ?9.10?
>
>    versions[tail(order(nv), 1)] # ok
>    ## [1] "9.10"
>
>    sort(nv, decreasing = TRUE)[1] # ok
>    ## [1] ?9.10?
>
>    versions[which.max(xtfrm(nv))] # ok
>    ## [1] "9.10"
>
>    versions[which.max(nv)] # error
>    ## Error in which.max(nv) : 'list' object cannot be coerced to
type 'double'
>
>
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Sorry if this is obvious, but `which.max()` is hard-coded in C, with a
step at the beginning that attempts to coerce the vector to numeric

https://github.com/r-devel/r-svn/blob/5e0a5f013292e56c73360addb61ddaa7d3ca16a2/src/main/summary.c#L1027

Another alternative (your methods are probably better?)

which.max.nv <- function(x) (seq_along(x)[x == max(x)])[1]

   It seems like too much work to change the definition of package versions
(which is a list of integer vectors, under the hood) or to make a generic
S3 method for which.max, given that the workarounds are so easy.

  Also, the documentation explicitly calls out this limitation:

x: numeric (logical, integer or double) vector or an R object
          for which the internal coercion to ?double? works whose ?min?
          or ?max? is searched for.



On Sat, Dec 20, 2025 at 10:35?AM Gabor Grothendieck <ggrothendieck at
gmail.com>
wrote:
>   versions <- c("9.10", "9.2")
>   nv <- numeric_version(versions)
>   class(nv)
>   ## [1] "numeric_version"
>
>   max(nv) # ok
>   ## [1] ?9.10?
>
>   versions[tail(order(nv), 1)] # ok
>   ## [1] "9.10"
>
>   sort(nv, decreasing = TRUE)[1] # ok
>   ## [1] ?9.10?
>
>   versions[which.max(xtfrm(nv))] # ok
>   ## [1] "9.10"
>
>   versions[which.max(nv)] # error
>   ## Error in which.max(nv) : 'list' object cannot be coerced to
type
> 'double'
>
>
> --
> Statistics & Software Consulting
> GKX Group, GKX Associates Inc.
> tel: 1-877-GKX-GROUP
> email: ggrothendieck at gmail.com
>
> ______________________________________________
> R-devel at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel
>
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