[Rd] Base R: applying min/max functions() to character string vectors (PR#9428)

[Duncan Murdoch]

On 12/22/2006 10:20 AM, xiao.gang.fan1 at libertysurf.fr wrote:
> Full_Name: Xiao Gang FAN
> Version: 2.4.0
> OS: Windows XP
> Submission from: (NULL) (159.50.101.9)
> 
> 
> Dear All,
> 
> This is not really a bug report, but rather a change wish to the Base R
> behaviour
> on some functions when applying them to character strings vectors/matrices.
> 
> Actually in R, we can do thinks like, the most naturally way in this the world:
>> "a" < "b"
> [1] TRUE
> 
>> order(c("b","a"))
> [1] 2 1
> 
>> pmax(c("a","b"), c("b"))
> [1] "b" "b"
> 
> 
> But helas, we can't do things like:
>> max(c("a","b"))
> Error in max(..., na.rm = na.rm) : invalid 'type' (character) of argument
> 
>> range(c("z","b","w","c"))
> Error in min(..., na.rm = na.rm) : invalid 'type' (character) of argument
> 
>> which.min(c("b","a"))
> integer(0)
> Warning message:
> NAs introduced by coercion 
> 
> I hope that you could understand the incoherence exhibited here 
> and my wish to see that to be changed some day, say in the becoming 
> year 2007. Here's a first list of functions to be reviewed: 
> min(), max(), which.min(), which.max(), range(), ...

That does seem like a reasonable change.  Why not submit a patch?  min 
and max are in https://svn.r-project.org/R/trunk/src/main/summary.c.  I 
haven't looked up the others, but it's possible they just call the 
internal code for min and max.

Duncan Murdoch