I have two dataframes as shown below:
Df1
| date | a | b |
|---|---|---|
| 2023-01-31 | 10 | john |
| 2022-02-30 | 15 | elle |
| 2020-03-04 | 20 | david |
Df2
| date | a |
|---|---|
| 2023-01-31 | 10 |
| 2022-02-30 | 30 |
| 2020-04-04 | 20 |
I want to extract the values in column b in Dataframe1 only when Df1$date = Df2$date AND Df1$a = Df2$a.
In the above example, the only row where both conditions match is row 1, so my output should be
| b |
|---|
| john |
How can I write this using sqldf in R or even using base R?
CodePudding user response：
You can use inner_join from dplyr package
library(dplyr)
df1 %>%
inner_join(df2, by = c("date", "a")) %>%
select(b) # as per @jpsmith comment
b
1 john