[R] Adding matrix rows that have the same name?

[Sarah Berke]

Does anyone know if there is an R function that will take a matrix like this

jim     1  0  0  0  0  0
jim     0  1  0  0  0  0
jim     0  0  1  0  0  0
bob    1  0  0  0  0  0
bob    0  0  1  0  0  0
harry  0  0  1  0  0  0
harry  0  0  0  1  0  0
harry  0  0  0  0  1  0
harry  0  0  0  0  0  1

and make it like this? (that is, add together rows that have the same name?)

jim    1 1 1 0 0 0
bob   1 0 1 0 0 0
harry 0 0 1 1 1 1


here's the code I started with, if it helps

library (dummies)
a <- c(1,1,1,2,2,3,3,3,3)
b<- c("A","B","C","A","C","C","D","E","F")
name<- c("jim", "jim", "jim", "bob", "bob", "harry", "harry", "harry", "harry")
MyMat <- cbind (a, b)
rownames (MyMat) <- name
dum.mat.temp <- dummy ("b", MyMat)
       #dum.mat.temp <-cbind (name, dum.mat.temp) # if you want names
as a column
dum.mat.temp

Many thanks in advance!
--Sarah