William Dunlap wrote:
...
if (x <= 0) NA else log(x)
variety otherwise.
Would you only want it to coerce upwards to FUN.VALUES's
type? E.g., allow
sapply(z, length, FUN.VALUE=numeric(1))
to return a numeric vector but die on
sapply(z, function(zi)as.complex(zi[1]), FUN.VALUE=numeric(1))
If the latter doesn't die should it return
a complex or a numeric vector? (I'd say it
needs to be numeric, but I'd prefer that it
died.)
I'd say that it should probably die on downwards coercion. Getting a
double when an integer is expected, or complex instead of double as you
indicate, is a likely user error. If not, then the user can always
coerce explicitly inside FUN.
Another issue is whether one would want to go beyond the base classes of
S (logical, integer, double, complex, character). For other classes,
there may be no notion of "up" and "down" in coercion. Then again,
sapply was always limited to what unlist() will handle, so e.g.
> sapply(1:10,FUN=function(i)Sys.Date())
[1] 14553 14553 14553 14553 14553 14553 14553 14553 14553 14553
as opposed to
> structure(rep(14553,10), class="Date")
[1] "2009-11-05" "2009-11-05" "2009-11-05" "2009-11-05" "2009-11-05"
[6] "2009-11-05" "2009-11-05" "2009-11-05" "2009-11-05" "2009-11-05"
--
O__ ---- Peter Dalgaard Øster Farimagsgade 5, Entr.B
c/ /'_ --- Dept. of Biostatistics PO Box 2099, 1014 Cph. K
(*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalga...@biostat.ku.dk) FAX: (+45) 35327907
______________________________________________
R-devel@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-devel
