Prof Brian Ripley wrote:
As the help page says
If some of the values are not vectors of the appropriate length,
you deserve whatever you get!
Yes (did I write that?). It is a bit annoying with things that almost
work, though.
[snip]
I often need to use this for creating new variables in data frame from
those already present.
Sorely needed!!
Just learn to use indexing: transform() is just syntactic sugar that you
are not making use of.
...at least when you're not making use of the scoping aspects. And if
you calculate at least one vector of full length, then the issue goes away.
> transform(aq, a=1,b=2)
Error in data.frame(`_data`, e[!matched]) :
arguments imply differing number of rows: 6, 1
> transform(aq, a=1,b=2,o=Ozone)
Ozone Solar.R Wind Temp Month Day a b o
3 12 149 12.6 74 5 3 1 2 12
31 37 279 7.4 76 5 31 1 2 37
34 NA 242 16.1 67 6 3 1 2 NA
65 NA 101 10.9 84 7 4 1 2 NA
59 NA 98 11.5 80 6 28 1 2 NA
133 24 259 9.7 73 9 10 1 2 24
The underlying issue is actually not in transform() but in data.frame():
> aq <- airquality[sample(1:153,6),]
> data.frame(aq, list(a=1,b=2))
Error in data.frame(aq, list(a = 1, b = 2)) :
arguments imply differing number of rows: 6, 1
> data.frame(aq, list(a=1))
Ozone Solar.R Wind Temp Month Day a
3 12 149 12.6 74 5 3 1
31 37 279 7.4 76 5 31 1
34 NA 242 16.1 67 6 3 1
65 NA 101 10.9 84 7 4 1
59 NA 98 11.5 80 6 28 1
133 24 259 9.7 73 9 10 1
--
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
~~~~~~~~~~ - ([EMAIL PROTECTED]) FAX: (+45) 35327907
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