R dplyr join by range or virtual column

Question

I want to join two tibbles by a range or a virtual column. but it seems the by - parameter just allow to handle chr oder vector(chr) o

Answer 1

I don't think inequality joins is implemented in dplyr yet, or it ever will (see this discussion on Join on inequality constraints), but this is a good situation to use an SQL join:

library(tibble)
library(sqldf)

as.tibble(sqldf("select d.value, r.class from d
                join r on d.value >= r.'from' and 
                          d.value < r.'to'"))

Alternatively, if you want to integrate the join into your dplyr chain, you can use fuzzyjoin::fuzzy_join:

library(dplyr)
library(fuzzyjoin)

d %>%
  fuzzy_join(r, by = c("value" = "from", "value" = "to"), 
             match_fun = list(`>=`, `<`)) %>%
  select(value, class)

Result:

# A tibble: 31 x 2
   value class
    
 1   1.0     A
 2   1.2     A
 3   1.4     A
 4   1.6     A
 5   1.8     A
 6   2.0     A
 7   2.0     B
 8   2.2     B
 9   2.4     B
10   2.6     B
# ... with 21 more rows

Notice I added single quotes around from and to since those are reserved words for the SQL language.