Check if a date is within an interval in R

Question

I have these three intervals defined:

YEAR_1  <- interval(ymd(\'2002-09-01\'), ymd(\'2003-08-31\'))
YEAR_2  <- interval(ymd(\'2003-09-01\'), ymd(\'20         


        

Answer 1

We can :

1st: create a data.table contains all YEAR_N

> interval.dt <- data.table(Interval = c(YEAR_1, YEAR_2, YEAR_3))
> interval.dt
#                         Interval
#1: 2002-09-01 UTC--2003-08-31 UTC
#2: 2003-09-01 UTC--2004-08-31 UTC
#3: 2004-09-01 UTC--2005-08-31 UTC

2nd: define a function to get row index of interval.dt when a specific year date fall in range interval.dt$Interval using int_start(interval.dt$Interval) < year < int_end(interval.dt$Interval)

>  findYearIndex <- function(year) {
      interval.dt[,which(int_start(interval.dt$Interval) < year & year < int_end(interval.dt$Interval))]
      }

3rd: sapply findYearIndex function to every element in year date data.table

> dt <- data.table(year = df)
> dt$YearIndex <- paste("YEAR", sapply(dt$year, findYearIndex), sep = "_")

> dt
  #         year       YearIndex
  #1: 2003-06-11          YEAR_1
  #2: 2004-08-11          YEAR_2
  #3: 2004-06-03          YEAR_2
  #4: 2004-01-20          YEAR_2
  #5: 2005-02-25          YEAR_3
  #6: 2003-01-07          YEAR_1
  #7: 2003-11-19          YEAR_2
  #8: 2003-03-12          YEAR_1
  #9: 2003-12-29          YEAR_2
 #10: 2003-03-26          YEAR_1
 #11: 2004-08-19          YEAR_2
 #12: 2004-07-19          YEAR_2
 #13: 2003-04-29          YEAR_1
 #14: 2003-05-06          YEAR_1
 #15: 2005-10-27 YEAR_integer(0)
 #ignore the rest of dt