如何同时对两个变量使用apply

suppose I have

假设我有

# test case
a<-matrix(rep(c(1,2,3,4,5,6),3),ncol=3)
b<-t(matrix(c(1,3,4)))

a

     [,1] [,2] [,3]
[1,]    1    1    1
[2,]    2    2    2
[3,]    3    3    3
[4,]    4    4    4
[5,]    5    5    5
[6,]    6    6    6

b

     [,1] [,2] [,3]
[1,]    1    3    4
# test case
a<-matrix(