Join overlapping ranges from two data frames in r - r

Question

Note: This question was closed as a 'duplicate'. The solutions offered here and here did not answer my question. They showed how to merge when a single entry fell within a range, I'm trying to identify overlapping ranges and joining them. Perhaps my title could have been better...
I have a main data set main_df with a start and end time (in seconds). I would like to see if the time range in main_df falls within a list of ranges in lookup_df, and if so, grab the value from lookup_df. Additionally, if the main_df falls within two different lookup ranges, duplicate the row so each value is represented.***
main_df <- tibble(start = c(30,124,161),
end = c(80,152,185))
lookup_df <- tibble(start = c(34,73,126,141,174,221),
end = c(69,123,136,157,189,267),
value = c('a','b','b','b','b','a'))
# Do something here to get the following:
> final_df
# A tibble: 4 x 4
start end value notes
<dbl> <dbl> <chr> <chr>
1 30 80 a ""
2 30 80 b "Duplicate because it falls within a and b"
3 124 152 b "Falls within two lookups but both are b"
4 161 185 b ""
***Edit: Looking at the way I've structured the problem...
#Not actual code
left_join(main_df, lookup_df, by(some_range_join_function) %>%
add_rows(through_some_means)
Rather than having to add a new row I could flip how I'm joining them...
semi_join(lookup_df, main_df, by(some_range_join_function))

Answer 1

You could do some logical comparisons and then a case handling what shall happen if all are 'b', 'a' and 'b', etc. In this way you easily could add more cases, e.g. both are 'a', one is 'a', more are 'b' which you didn't declare in OP. The approach yields NULL if there are no matches which gets omitted during rbind.
f <- \(x, y) {
w <- which((x[1] >= y[, 1] & x[1] <= y[, 2]) | (x[2] >= y[, 1] & x[1] <= y[, 2]))
if (length(w) > 0) {
d <- data.frame(t(x), value=cbind(y[w, 3]), notes='')
if (length(w) >= 2) {
if (all(d$value == 'b')) {
d <- d[!duplicated(d$value), ]
d$notes[1] <- 'both b'
}
else {
d$notes[nrow(d)] <- 'a & b'
}
}
d
}
}
apply(main_df, 1, f, lookup_df, simplify=F) |> do.call(what=rbind)
# start end value notes
# 1 30 80 a
# 2 30 80 b a & b
# 3 124 152 b both b
# 4 161 185 b
Data:
main_df <- structure(list(start = c(2, 30, 124, 161), end = c(1, 80, 152,
185)), row.names = c(NA, -4L), class = "data.frame")
lookup_df <- structure(list(start = c(34, 73, 126, 141, 174, 221), end = c(69,
123, 136, 157, 189, 267), value = c("a", "b", "b", "b", "b",
"a")), row.names = c(NA, -6L), class = "data.frame")

Answer 2

Another option is fuzzyjoin::interval_join:
library(fuzzyjoin)
library(dplyr)
interval_join(main_df, lookup_df, by = c("start", "end"), mode = "inner") %>%
group_by(value, start.x, end.x) %>%
slice(1) %>%
select(start = start.x, end = end.x, value)
# A tibble: 4 × 3
# Groups: value, start, end [4]
start end value
<dbl> <dbl> <chr>
1 30 80 a
2 30 80 b
3 124 152 b
4 161 185 b

Answer 3

You can use foverlaps from data.table for this.
library(data.table)
setDT(main_df) # make it a data.table if needed
setDT(lookup_df) # make it a data.table if needed
setkey(main_df, start, end) # set the keys of 'y'
foverlaps(lookup_df, main_df, nomatch = NULL) # do the lookup
# start end i.start i.end value
# 1: 30 80 34 69 a
# 2: 30 80 73 123 b
# 3: 124 152 126 136 b
# 4: 124 152 141 157 b
# 5: 161 185 174 189 b
Or to get the cleaned results as end result (OP's final_df)
unique(foverlaps(lookup_df, main_df, nomatch = NULL)[, .(start, end, value)])
start end value
1: 30 80 a
2: 30 80 b
3: 124 152 b
4: 161 185 b

Answer 4

A possible solution, based on powerjoin:
library(tidyverse)
library(powerjoin)
power_left_join(
main_df, lookup_df,
by = ~ (.x$start <= .y$start & .x$end >= .y$end) |
(.x$start >= .y$start & .x$start <= .y$end) |
(.x$start <= .y$start & .x$end >= .y$start),
keep = "left") %>%
distinct()
#> # A tibble: 4 x 3
#> start end value
#> <dbl> <dbl> <chr>
#> 1 30 80 a
#> 2 30 80 b
#> 3 124 152 b
#> 4 161 185 b
Or using tidyr::crossing:
library(tidyverse)
crossing(main_df, lookup_df,
.name_repair = ~ c("start", "end", "start2", "end2", "value")) %>%
filter((start <= start2 & end >= end2) |
(start >= start2 & start <= end2) | (start <= start2 & end >= start2)) %>%
select(-start2, -end2) %>%
distinct()
#> # A tibble: 4 x 3
#> start end value
#> <dbl> <dbl> <chr>
#> 1 30 80 a
#> 2 30 80 b
#> 3 124 152 b
#> 4 161 185 b

Answer 5

You can use the fuzzyjoin package to join based on intervals with the fuzzyjoin::interval_*_join() functions.
I'll be using an inner join, because if you use a semi join like you propose, you will loose the value col and get just 3 rows.
library(tidyverse)
library(fuzzyjoin)
fuzzyjoin::interval_inner_join(lookup_df, main_df, by = c("start", "end"), type = "any")
#> # A tibble: 5 × 5
#> start.x end.x value start.y end.y
#> <dbl> <dbl> <chr> <dbl> <dbl>
#> 1 34 69 a 30 80
#> 2 73 123 b 30 80
#> 3 126 136 b 124 152
#> 4 141 157 b 124 152
#> 5 174 189 b 161 185
As you can see, the fuzzy_inner_join() preserves the by cols from both tables, since they are not the same in a fuzzy join. Also, we still have separate rows for those cases in main_df that match multiple cases in lookup_df. Thus, we do some cleanup of the joined table:
interval_inner_join(lookup_df, main_df,
by = c("start", "end"),
type = "any") |>
select(-ends_with(".x")) |> # remove lookup interval cols
distinct() |> # remove duplicate
rename_with(str_remove, ends_with(".y"), "\\.y") # remove suffixes from col names
#> # A tibble: 4 × 3
#> value start end
#> <chr> <dbl> <dbl>
#> 1 a 30 80
#> 2 b 30 80
#> 3 b 124 152
#> 4 b 161 185
Finally, a clarification of terminology: In your question you state you want to join based on the interval from main_df falling within the interval from lookup_df. This is possible by using type = "within" in interval_*_join(). But based on the examples you provide, it appears you want to join based on any overlap. This can be done with type = "any", but it is the default, so you don't need to specify it.