[R] matching identical row names

[Srinivas Iyyer]

dear group, 
 
i have a sample matrix
name   v1   v2   v3   v4
cat   10    11   12   15
dog   3     12   10   14
cat   9     12   12   15
cat   5     12   10   11
dog   12    113  123  31
...


since cat is repeated 3 times, I want a mean value for
it. Like wise for every element of the name column. 
cat v1 = mean(c(10,9,5))
cat v3 = mean(c(11,12,13))
..etc.

name v1   v2     v3   v4
cat  8   11.6   11.3  13.6
dog  7.5 62.5   66.5  22.5

could any one help me in solving this mystery. thank you.