For reference: this is about
<https://bugs.r-project.org/show_bug.cgi?id=17616>.
The problem with your 'contr.none' example is that it is not a proper
contrasts function (and has never been). ?contrasts says
> Suitable
> functions have a first argument which is the character vector of
> levels, a named argument 'contrasts' (always called with
> 'contrasts = TRUE') and optionally a logical argument
'sparse'.
Your example function fails also in R 4.1.3 and 4.2.1:
> contr.none <- function(n) contrasts(factor(1:n), contrasts = FALSE)
> contrasts(CO2$Treatment) <- "contr.none"
> contrasts(CO2$Treatment)
Error in ctrfn(levels(x), contrasts = contrasts) :
unused argument (contrasts = contrasts)
Even if we fix the missing argument:
> contr.none <- function(n, ...) contrasts(factor(1:n), contrasts = FALSE)
> contrasts(CO2$Treatment) <- "contr.none"
> contrasts(CO2$Treatment)
Error in 1:n : NA/NaN argument
In addition: Warning messages:
1: In 1:n : numerical expression has 2 elements: only the first used
2: In factor(1:n) : NAs introduced by coercion
What *did* work (inconsistently) was :
> contrasts(CO2$Treatment) <- contr.none
> contrasts(CO2$Treatment)
1
nonchilled 1
chilled 0
It no longer does in R-devel as 'contr.none' is now called with the
factor *levels* (not nlevels) also in this case as documented.
Note that the argument name 'n' in the default contrast functions such
as contr.treatment() is a bit delicate as these support passing either
levels or nlevels.
Hope this helps.
Best regards,
Sebastian Meyer
Am 30.06.22 um 00:27 schrieb Murray Efford:> This worked previously but gives an error in R-devel (Windows today),
triggering a warning to a package maintainer:
>
> contr.none <- function(n) contrasts(factor(1:n), contrasts = FALSE)
> lm(uptake~Treatment, CO2, contrasts=list(Treatment=contr.none))
>
> Error in 1:n : NA/NaN argument
> In addition: Warning messages:
> 1: In 1:n : numerical expression has 2 elements: only the first used
> 2: In factor(1:n) : NAs introduced by coercion
>
> ______________________________________________
> R-devel at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel