How to sort data in table

Question

I have a matrix:

m = matrix(c(c(1,4,2,5,8,5)), ncol=2)
colnames(m)<-c("a", "b")

so I have:

     a b
[1,] 1 5
[2,] 4 8
[3,] 2 5

How to sort for example by column a?

@nrussell IMO you should post as an answer. – jlhoward Oct 08 '15 at 15:27 — jlhoward, Oct 08 '15 at 15:27

score 1 · Accepted Answer · answered Oct 08 '15 at 15:31

1

You can accomplish this with base::order:

R> m[order(m[,"a"]), ]
#     a b
#[1,] 1 5
#[2,] 2 5
#[3,] 4 8

answered Oct 08 '15 at 15:31

nrussell

score 0 · Answer 2 · answered Oct 08 '15 at 15:04

0

Use the dplyr package. But this change to a data.frame... but you can easily change it back

#install.packages(dplyr)
library(dplyr)
M <- arrange(as.data.frame(m), a) 
#change back
m <- as.matrix(M)

answered Oct 08 '15 at 15:04

njBernstein

2 Answers2