Hi--
I suspect this is a frequently considered (and possibly asked) question, but I
haven't thus far found an answer:
For slicing a vector with x[…], is there a symbol for length(x)?
I'm seeking a short-hand for referring to the length of vector one is trying to
index.
E.g., for a data.frame, say,
> test.frame <-data.frame(matrix(c(1:100),ncol=10,nrow=10,byrow=T))
> names(test.frame) <- names(islands)[1:10]
is there a short-hand for subsetting
> test.frame$Baffin[1:(length(test.frame$Baffin)-3)]
[1] 6 16 26 36 46 56 66
>
>
that would allow one to avoid the "(length(some.dataframe$variable)-offset)"?
I was thinking something paralleling the use of negative indices in […] might
exist with seq(from,to), e.g. for the above
> test.frame$Baffin[seq(,7)]
[1] 6 16 26 36 46 56 66
>
works. But the fantasy
test.frame$Baffin[seq(,-3)]
obviously doesn't…
Any suggestions will be gratefully appreciated…
As always, many thanks to the patient list members who helps on these simple
questions...
Best,
Eric
--
Eric Rupley
University of Michigan, Museum of Anthropology
1109 Geddes Ave, Rm. 4013
Ann Arbor, MI 48109-1079
erup...@umich.edu
+1.734.276.8572
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