I realize that dplyr v3.0 allows you to join on different variables:
left_join(x, y, by = c("a" = "b") will match x.a to y.b
However, is it possible to join on a combination of variables or do I have to add a composite key beforehand?
Something like this:
left_join(x, y, by = c("a c" = "b d") to match the concatenation of [x.a and x.c] to [y.b and y.d]
1 Answer
Updating to use tibble()
You can pass a named vector of length greater than 1 to the by argument of left_join():
library(dplyr) d1 <- tibble( x = letters[1:3], y = LETTERS[1:3], a = rnorm(3) ) d2 <- tibble( x2 = letters[3:1], y2 = LETTERS[3:1], b = rnorm(3) ) left_join(d1, d2, by = c("x" = "x2", "y" = "y2")) 
