现有原始数据A<-data.frame(IP=c("001","002","003","002","001"),IC=c("a","b","c","d","e"),IE =c(1,2,3,4,5))，条件数据为
B<-data.frame(IP=c("002","001"),IE =c(2,1))，
如何得到数据C<-data.frame(IP=c("002","001"),IC=c("b","a"),IE =c(2,1))，求大虾指教下{:3_57:}