This is FAQ 7.17:
http://cran.r-project.org/doc/FAQ/R-FAQ.html#Why-does-outer_0028_0029-behave-strangely-with-my-function_003f
On 7/19/06, Ritwik Sinha <ritwik.sinha at gmail.com>
wrote:> Hi,
>
> I am trying to rearrange the following data
>
> d.f <- data.frame(x=c(1,1,2,2), y=c(1,2,1,2), vals=c("a11",
"a12",
> "a21", "a22"))
>
> to look like a table with x as the rows and y as the columns, something
like
>
> y 1 2
> x
> 1 a11 a12
> 2 a21 a22
>
> I tried doing this
>
> funny <- function(x,y){d.f[d.f$x==x & d.f$y==y,3]}
>
> outer(1:2,1:2, FUN="funny")
> But get the error
>
> Error in outer(1:2, 1:2, FUN = "funny") : dim<- : dims
[product 4] do
> not match the length of object [2]
>
> What am I doing wrong? I am sure there are a hundred different ways of
> doing this.
>
> version
>
> platform i486-pc-linux-gnu
> arch i486
> os linux-gnu
> system i486, linux-gnu
> status
> major 2
> minor 2.1
> year 2005
> month 12
> day 20
> svn rev 36812
> language R
>
> --
> Ritwik Sinha
> Graduate Student
> Epidemiology and Biostatistics
> Case Western Reserve University
>
> http://darwin.cwru.edu/~rsinha
>
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