使用R合并和替换重复值

Question

我有 2 个数据框，想合并，但如果有相同的值必须将其替换为 NA，例如

df1=data.frame(x1=c(1,1,1,2,2,2,2),x2=c("a","a","b","b","c","c","c"),x3=c("t","u","v","w","x","y","z"),x4=c("apple","apple","mango","mango","mango","mango","mango"))

df2=data.frame(x1=c(1,1,1,1,2,2,2,2),x2=c("a","a","a","b","b","b","c","c"),x3=c("t","u","u","v","w","x","y","z"),x5=c("apple A","apple A","apple B","mango A","mango B","mango A","mango A","mango A"),x6=c(10,10,20,10,10,30,30,30))

我的预期df

df3=data.frame(x1=c(1,1,1,1,2,2,2,2),x2=c("a","a","a","b","b","b","c","c"),x3=c("t","u","u","v","w","x","y","z"),x4=c("apple","apple","apple","mango","mango","mango","mango","mango"),x5=c("apple A","apple A","apple B","mango A","mango B","mango A","mango A","mango A"),x6=c(10,NA,20,10,10,30,30,NA))

合并 df1 和 df2，但如果 df2 在 x1、x2 和 x5 上有重复值，则 x6 为 NA

Answer 1

考虑做：

is.na(df2$x6) <- duplicated(df2[c('x1' , 'x2', 'x5', 'x6')])
merge(df1, df2, all.x = TRUE)

  x1 x2 x3    x4      x5 x6
1  1  a  t apple apple A 10
2  1  a  u apple apple A NA
3  1  a  u apple apple B 20
4  1  b  v mango mango A 10
5  2  b  w mango mango B 10
6  2  c  x mango    <NA> NA
7  2  c  y mango mango A 30
8  2  c  z mango mango A NA