[R] convert a data.frame to matrix
David Winsemius
dwinsemius at comcast.net
Fri May 17 01:59:16 CEST 2013
On May 16, 2013, at 1:46 PM, Hermann Norpois wrote:
> Hello,
>
> I fail to tranfer data from a dataframe to a matrix.
>
> jam is from a dataframe (and belongs still to the class dataframe) and
> should look like m (see below).
>
>> jam
> vec1 vec3 d1 d2
> 1 172 173 223 356
>> dput (jam)
> structure(list(vec1 = 172L, vec3 = 173L, d1 = 223L, d2 = 356L), .Names =
> c("vec1",
> "vec3", "d1", "d2"), row.names = 1L, class = "data.frame")
>> m #THIS IS THE AIM
> [,1] [,2]
> [1,] 172 223
> [2,] 173 356
>
>> dput (m)
> structure(c(172, 173, 223, 356), .Dim = c(2L, 2L))
>
> How can I transform jam to m?
jam <- structure(list(vec1 = 172L, vec3 = 173L, d1 = 223L, d2 = 356L), .Names =
c("vec1",
"vec3", "d1", "d2"), row.names = 1L, class = "data.frame")
jm <- data.matrix(jam)
dim(jm) <- c(2,2) # re-dimension a matrix with column-major order
jm
[,1] [,2]
[1,] 172 223
[2,] 173 356
> Thanks
> Hermann
>
> [[alternative HTML version deleted]]
>
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David Winsemius
Alameda, CA, USA
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