dplyr match variable with multiple columns

Asked Jul 07 '16 at 18:13

Active Jul 07 '16 at 18:13

Viewed 67 times

I have a quite large data frame containing among others two columns: towns and counties, and a bunch of lines corresponding to combinations of the two. I would like to get a new column with a unique ID for every combinations. I could probably do it in base R, but I am trying to convert to dplyr for this project.

The following code gives me an ID for each combination of two variables in the data frame.

library(dplyr)

dd <- data.frame(x = sample(letters[1:10], 100, TRUE), y = sample(letters[1:10], 100, TRUE))


id <- dd %>% distinct(x, y) %>% mutate(1:n())

How can add this id variable back to dd in the correct positions?

asked Jul 07 '16 at 18:13

Theodor

1

Try `left_join(dd, id)` – akrun Jul 07 '16 at 18:15
A little hacky, but maybe easier: `dd %>% mutate(id = as.integer(factor(paste(x, y))))` – alistaire Jul 07 '16 at 18:19
2

Or another way of writting @alistaire's suggestion: `dd %>% mutate(id=as.numeric(interaction(x,y)))` – MrFlick Jul 07 '16 at 18:20
Related to this github issue: https://github.com/hadley/dplyr/issues/1185 – MrFlick Jul 07 '16 at 18:23

dplyr match variable with multiple columns

0 Answers0