Subsetting rows and columns with given indices

Asked Jan 21 '16 at 00:32

Active Jan 21 '16 at 00:32

Viewed 39 times

I wish to subset a matrix/ data.frame with a set of indices that I have. For instance if I do:

a=matrix(1:20,4)
a[1:2,1:2]
     [,1] [,2]
[1,]    1    5
[2,]    2    6

However, I was hoping to only get a[1,1] and a[2,2] only. How can you do this in R without using a for loop.

asked Jan 21 '16 at 00:32

sachinruk

5

`a[rbind(c(1, 1), c(2, 2))]` – G. Grothendieck Jan 21 '16 at 00:33
Do you want to put this as an answer so I can mark as solved? – sachinruk Jan 21 '16 at 00:57
Looks like @thelatemail found it answered already. – G. Grothendieck Jan 21 '16 at 01:33

0 Answers0