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