相关疑难解决方法(0)

复杂的标题,但这是我想要实现的一个简单的例子:

d <- data.frame(v1 = c(1,2,3,4,5,6,7,8), 
                v2 = c("A","E","C","B","B","C","A","E"))

m <- data.frame(v3 = c("D","E","A","C","D","B"), 
                v4 = c("d","e","a","c","d","b"))

在价值d$v2应该由值来代替m$v4从值相匹配d$v2的m$v3

生成的数据框d应如下所示:

v1    v4
1      a
2      e
3      c
4      b
5      b
6      c
7      a
8      e

我尝试了不同的东西,我最接近的是: d$v2 <- m$v4[which(m$v3 %in% d$v2)]

我试着再次避免任何for循环!必须是可能的:-)不知怎的......;)