R-alpha: na.woes
Peter Dalgaard BSA
p.dalgaard@kubism.ku.dk
23 Oct 1997 00:41:55 +0200
1) hist() does not take NA's. Incompatible with Splus, probably just a
bug?
2) I do wish we could somehow get rid of the misfeatures of indexing
with logical NA's:
> table(juul$menarche,juul$tanner)
I II III IV V
No 221 43 32 14 2
Yes 1 1 5 26 202
> juul$menarche=="Yes"&juul$tanner=="I",]
...and you find yourself with a listing of 477 cases, of which the 476
are NA-filled. To find the interesting case, you need to go through
the following contortions:
> menar.t1 <- juul$menarche=="Yes"&juul$tanner=="I"
> menar.t1 <- menar.t1 & !(is.na(menar.t1))
> juul[menar.t1,]
age menarche sex igf1 tanner testvol
962 12.33 Yes F NA I NA
I can't think of a single case where the current behavior is useful.
Indexing with numerical NA's makes sense, e.g. when recoding, and then
there's the boundary case of indexing with a vector where all elements
are logical NA's (should they be promoted to numeric?), but situations
where they arise naturally are pretty hard to think up.
Current behavior is Splus-compatible, but its still annoying.
--------------------
BTW, re. case labels, R is *not* Splus-compatible:
R:
> menar.t1[1]<-NA
> juul[menar.t1,]
age menarche sex igf1 tanner testvol
NA NA NA NA NA NA NA
962 12.33 Yes F NA I NA
> menar.t1[2]<-NA
> juul[menar.t1,]
Warning: some row names are duplicated; argument ignored
age menarche sex igf1 tanner testvol
[1,] NA NA NA NA NA NA
[2,] NA NA NA NA NA NA
[3,] 12.33 Yes F NA I NA
Splus:
> data[c(T,NA,rep(F,14)),]
x1 x2 x3 x4 migraine not.migraine
1 0 0 0 0 25 546
NA NA NA NA NA NA
> data[c(T,NA,NA,rep(F,13)),]
x1 x2 x3 x4 migraine not.migraine
X1 0 0 0 0 25 546
X NA NA NA NA NA NA
X11 NA NA NA NA NA NA
Somehow, I don't think we should strive for compatibility on this
point...
--
O__ ---- Peter Dalgaard Blegdamsvej 3
c/ /'_ --- Dept. of Biostatistics 2200 Cph. N
(*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard@biostat.ku.dk) FAX: (+45) 35327907
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