On Sep 3, 2010, at 9:08 AM, syrvn wrote:
Hi,
the R code:
a <-
matrix
(c(1,5,4,3,7,10,34,4,3,8,6,5,12,17,45,3,2,45,46,47,3,4,22,12,21),
nrow=5)
rownames(a) <- c("a","b","c","d","e")
a
a[which(a[,3] < 8), ]
a[which(a[,3] < 6), ]
It wasn't exactly clear and possible that you wanted only rownames
that satisfied those criteria
> rownames(a)[which(a[,3] < 8)]
[1] "a" "b"
> rownames(a)[which(a[,3] < 6)]
[1] "b"
> rownames(a)[which(a[,3] < 4)]
character(0)
Sometimes which() is needed, and others it is not. This appears to be
one where it is not needed:
> rownames(a)[a[,3] < 4]
character(0)
> rownames(a)[a[,3] < 6]
[1] "b"
> rownames(a)[a[,3] < 8]
[1] "a" "b"
--
David.
produces the following output:
a
[,1] [,2] [,3] [,4] [,5]
a 1 10 6 3 3
b 5 34 5 2 4
c 4 4 12 45 22
d 3 3 17 46 12
e 7 8 45 47 21
a[which(a[,3] < 8), ]
[,1] [,2] [,3] [,4] [,5]
a 1 10 6 3 3
b 5 34 5 2 4
a[which(a[,3] < 6), ]
[1] 5 34 5 2 4
I actually thought it must be rather easy to somehow extract the row
name
when the result is just a vector as in the second example and not a
matrix.
I tried several ways but without any success.
Any advice?
Best,
syrvn
--
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David Winsemius, MD
West Hartford, CT
______________________________________________
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