(Sorry, I think that I just hit a wrong button and managed
to send a non-reply.)
I think that David might have meant that the column order of the
numbers in lookfor is unimportant. In that case, a simple fix would
be either to check both lookfor and rev(lookfor) (since the
matrix is nX2) or to sort before testing:
vtest <- function(x, lookfor){
any(apply(x, 1, function(v)
{identical(sort(v), sort(lookfor))}))}
-Peter Ehlers
On 2010-03-27 2:46, Berend Hasselman wrote:
David Scott-6 wrote:
I am sure someone can come up with a clever way of doing what I want---I
don't seem to be able to.
I want to check if a pair of numbers occurs as one of the rows of an n
by 2 matrix. If I was only checking whether a single number was in a
vector of numbers I would use %in% but I can't see how to generalize to
this case.
Would this help?
vtest<- function(x, lookfor) any(apply(x,1, function(v)
identical(v,lookfor)))
ma<- matrix(c(2,3,1,5,7,3),ncol=2)
ma
[,1] [,2]
[1,] 2 5
[2,] 3 7
[3,] 1 3
vtest(ma,c(3,7))
[1] TRUE
vtest(ma,c(1,7))
[1] FALSE
Berend
--
Peter Ehlers
University of Calgary
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