如何根据另一个数据帧更新可变值，就像SQL中的更新函数一样

Question

如何根据DF_B更新DATAFRAME DF_A？结果为df_a update

library(tidyverse)
DF_A <- data.frame(CAT=c("A","B","C","D","E","F","G"))


DF_B <-data.frame(CAT=c("A","C","F"),
CAT_NEW=c("XZ","TF","ZE"))


DF_A_update <- data.frame(CAT=c("XZ","B","TF","D","E","ZE","G"))

Answer 1

您可以尝试加入这两个data.frames并替换CAT中的值，例如：

DF_A |> 
  dplyr::left_join(DF_B, by = "CAT") |> 
  dplyr::mutate(CAT = dplyr::if_else(is.na(CAT_NEW), CAT, CAT_NEW)) |> 
  dplyr::select(CAT) -> DF_NEW

identical(DF_NEW, DF_A_update)