通过合并多个列来更新列 [英] Update columns by joining more than one columns

问题描述

我有两个表，我需要从第二个表中的 pro_sales 值更新第一个表中的pro_sales列值。

I have two tables and I need to update pro_sales column values in the first table from pro_sales values in the second.

df1 <- data.frame(storecode = c(100,100,100,200,200),
                  productcode = c(1,2,3,1,2), pro_sales = c(0,0,0,0,0))
df2 <- data.frame(storecode = c(100,100,200),
                  productcode = c(1,2,1), pro_sales = c(0,1,0))

我需要在 storecode 和 productcode 列上左联接。下面应该是我的决赛桌：

I need to left join on the columns storecode and productcode. Below should be my final table:

  storecode productcode  pro_sales
1       100           1         0
2       100           2         1
3       100           3         0
4       200           1         0
5       200           2         0 

我能够退出dplyr，但是之后我需要帮助吗？

I was able to left join in dplyr but after that i need help please?

df1 %>%
  left_join(df2,c("storecode"="storecode","productcode"="productcode")) %>% 
  mutate( ???? ) %>%
  select(names, match, value = value.x)

谢谢。

推荐答案

另一个选择是对 data.table -package使用更新联接：

Another option is to use an update join with the data.table-package:

library(data.table)
setDT(df1)
setDT(df2)

df1[df2, on = .(storecode, productcode), pro_sales := i.pro_sales][]

给出

   storecode productcode pro_sales
1:       100           1         0
2:       100           2         1
3:       100           3         0
4:       200           1         0
5:       200           2         0

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