[R] Sort matrix with duplicate row names alphabetically by rowname

Paul Geeleher paulgeeleher at gmail.com
Mon May 19 13:06:33 CEST 2008


Hi,

I've a matrix that contains 4 replicates of each rowname. (4 a's, 4
b's, 4 c's in no particular order) Like this:


   #
c 32
a 1
b 4
c 87
c 34
b 54
a 23
a 12
b 9
a 3
b 87
c 43


There are a couple of more columns but I'm using the above as an example

 I need to sort it so that the same rownames appear together in
alpahbetical order. Like this:

  #
a 1
a 23
a 12
a 3
b 4
b 54
b 9
b 87
c 87
c 34
c 43
c 32


The code I came up with is something like this:

mat <- mat[sort(rownames(mat)), ]

This doesn't work though, it returns the same value for each row each
time, something like this:

  #
a 1
a 1
a 1
a 1
b 4
b 4
b 4
b 4
c 32
c 32
c 32
c 32

Any ideas how I could get my code to distinguish between the different
rows and get the output I'm looking for?

Thanks,

-Paul



More information about the R-help mailing list