R: Determine if each date interval overlaps with all other date intervals in a dataframe

Question

For each date interval row in my dataframe, I would like to determine whether it overlaps with all other date intervals or not. Excluding itself.

A dataframe with start and end date, representing intervals:

`data <- read.table(header=TRUE,text="
start.date             end.date
2019-09-01             2019-09-10
2019-09-05             2019-09-07
2019-08-25             2019-09-05
2019-10-10             2019-10-15
")`

This function lubridate::int_overlaps() checks if two date intervals overlap or not by returning logical TRUE or FALSE.

`int_overlaps(interval(ymd("2019-09-01"),ymd("2019-09-10")), interval(ymd("2019-09-05"), ymd("2019-09-07")))
[1] TRUE
int_overlaps(interval(ymd("2019-09-01"),ymd("2019-09-10")), interval(ymd("2019-10-10"), ymd("2019-10-15")))
[1] FALSE`

I would like to iterate each date interval with the all other date intervals excluding itself using int_overlap() to determine whether it overlaps with other date or not.

The output should look like this:

`data <- read.table(header=TRUE,text="
start.date             end.date         overlaps
2019-09-01             2019-09-10       TRUE
2019-09-05             2019-09-07       TRUE
2019-08-25             2019-09-05       TRUE
2019-10-10             2019-10-15       FALSE
")
`

Answer 1

Here is one option using dplyr and purrr, we loop through Int's indexes comparing the current interval with the other intervals.

library(dplyr)
library(purrr)
library(lubridate)
data %>% mutate(Int = interval(start.date, end.date), 
                overlaps = map(seq_along(Int), function(x){
                  #browser()
                  #Get all Int indexes other than the current one
                  y = setdiff(seq_along(Int), x)
                  #The interval overlaps with all other intervals
                  #return(all(int_overlaps(Int[x], Int[y])))
                  #The interval overlaps with any other intervals
                  return(any(int_overlaps(Int[x], Int[y])))
                }))

  start.date   end.date                            Int overlaps
1 2019-09-01 2019-09-10 2019-09-01 UTC--2019-09-10 UTC     TRUE
2 2019-09-05 2019-09-07 2019-09-05 UTC--2019-09-07 UTC     TRUE
3 2019-08-25 2019-09-05 2019-08-25 UTC--2019-09-05 UTC     TRUE
4 2019-10-10 2019-10-15 2019-10-10 UTC--2019-10-15 UTC    FALSE