How to specify names of columns for x and y when joining in dplyr?

Question

I have two data frames that I want to join using dplyr. One is a data frame containing first names.

test_data <- data.frame(first_name = c(\"john\", \"bil         


        

Answer 1

This feature has been added in dplyr v0.3. You can now pass a named character vector to the by argument in left_join (and other joining functions) to specify which columns to join on in each data frame. With the example given in the original question, the code would be:

left_join(test_data, kantrowitz, by = c("first_name" = "name"))

Answer 2

This is more a workaround than a real solution. You can create a new object test_data with another column name:

left_join("names<-"(test_data, "name"), kantrowitz, by = "name")

     name gender
1    john      M
2    bill either
3 madison      M
4    abby either
5     zzz   <NA>