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How to get row index number for particular name(s)?

Tags:

r

rows

rowname

How can one determine the row index-numbers corresponding to particular row names? I have a vector of row names, and I would like to use these to obtain a vector of the corresponding row indices in a matrix.

I tried row() and as.integer(rownames(matrix.object)), but neither seems to work.

like image 657
Roger Avatar asked Dec 08 '22 10:12

Roger


2 Answers

In addition to which, you can look at match:

m <- matrix(1:25, ncol = 5, dimnames = list(letters[1:5], LETTERS[1:5]))
vec <- c("e", "a", "c")
match(vec, rownames(m))
# [1] 5 1 3
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A5C1D2H2I1M1N2O1R2T1 Avatar answered Jan 04 '23 17:01

A5C1D2H2I1M1N2O1R2T1


Try which:

which(rownames(matrix.object) %in% c("foo", "bar"))
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sgibb Avatar answered Jan 04 '23 15:01

sgibb