相关疑难解决方法(0)

我有两个data.tables,一个有另一个的行/列子集.我想将较小的data.table的值添加到较大的值的值:

DT1 <- as.data.table(matrix(c(0, 1, 2, 3), nrow=2, ncol=2, 
       dimnames=list(c("a", "b"), c("a", "b"))), keep=T)
DT2 <- as.data.table(matrix(c(0, 0, 1, 2, 2, 1, 1, 0, 3), nrow=3, ncol=3, 
       dimnames=list(c("a", "b", "c"), c("a", "b", "c"))), keep=T)

DT1
#   rn a b
#1:  a 0 2
#2:  b 1 3
DT2
#   rn a b c
#1:  a 0 2 1
#2:  b 0 2 0
#3:  c 1 1 3

我想将DT1添加到DT2,以便我得到

#   rn a b c
#1:  a 0 4 1
#2: …