如果条目与另一列R匹配，则在数据框中交换单元格

Question

我有两个数据框：

start<- data.frame(gene=c("A","A","A","B","B"), isoform=c("A.1","A.1","A.1","B.1","B.1"), exon=c("1","2","3","1","2"))

replace<-data.frame(isoform=c("A.1","B.1"),gene=c("C","D"))

我想将df1中的基因条目与df2中与同种型匹配的基因条目互换 即以

结尾

result<-data.frame(gene=c("C","C","C","D","D"), isoform=c("A.1","A.1","A.1","B.1","B.1"), exon=c("1","2","3","1","2"))