It is unclear what you really want so here are two solutions to two
different questions:
> A <- matrix(c(0,1,2,0,1,0,1,2,3,4), ncol=1)
> A
[,1]
[1,] 0
[2,] 1
[3,] 2
[4,] 0
[5,] 1
[6,] 0
[7,] 1
[8,] 2
[9,] 3
[10,] 4
> A[A[,1] %in% c(2,1,4) , ]
[1] 1 2 1 1 2 4
# the value of the entries in the rows where that attains.
# not interesting in itself other than allowing a count,
# but possibly useful if you were interested in a matrix with more
columns
> which(A[,1] %in% c(2,1,4) )
[1] 2 3 5 7 8 10
#the row numbers where membership in that set occurs.
On Apr 28, 2009, at 10:35 PM, sangduan jansomboon wrote:
Hi all,
I have a problem selecting some rows from a random data.
I'd like to select the same rows (before 0) .
For example:
A
[1] 0
[2] 1
[3] 2
[4] 0
[5] 1
[6] 0
[7] 1
[8] 2
[9] 3
[10] 4
I'd like to select the row where a = 2 1 4
I searched on the search of the R site but I did'nt find anything of
simple.
Can someone help me?
David Winsemius, MD
Heritage Laboratories
West Hartford, CT
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