How to extract Business Hours between two different times values

Question

For the evaluation of tickets processed by a help desk I would like to know how many business hours an ticket is active. I can easily subtract the times and get the total amount

Answer 1

I have tried the solutions of both @mvan and @Steffan Jansson. Unfortunately they both didn't suit my needs. The first returns incorrect information. The latter is to slow for my requirements and doesn't take daylight saving time into account.

I created a function that is quicker and does take daylight saving into account. You can specify business hours and holidays.

Usage

The function accepts 5 arguments. 3 of them are optional.

1. The start time stamp (POSIXct)
2. The end time stamp (POSIXct)
3. The starting time of a business day (string: '00:00' to '24:00')
4. The ending time of a business day (string: '00:00' to '24:00')
5. A list of holidays (list of dates (as.Date))

Example:

start <- as.POSIXct('2014-09-27 10:12:37', tz = 'Europe/Amsterdam')
end <- as.POSIXct('2016-12-10 20:04:18', tz = 'Europe/Amsterdam')

biz_hrs(start, end, '10:00', '17:00')

You can also run it on dataframe columns. Make sure that every value is formatted properly. If an end value is older than a start value, the function returns NA. To change that edit line 6

Code

library(lubridate)


biz_hrs <- Vectorize(function(start, end, starting_time = '9:00', ending_time = '17:00', holidays = NULL){


      if(end < start){

        return(NA)

      } else {

        start_datetime <- as.POSIXct(paste0(substr(start,1,11), starting_time, ':00'))
        end_datetime <- as.POSIXct(paste0(substr(end,1,11), ending_time, ':00'))

        if(as.Date(start) == as.Date(end) & !as.Date(start) %in% holidays & !format(as.Date(start), "%u") %in% c(6,7)){ #if starting time stamp is on same day as ending time stamp and if day is not a holiday or weekend

          if(start > start_datetime & end < end_datetime){ #if starting time stamp is later than start business hour and ending time stamp is earlier then ending business hour.
            return(as.numeric(difftime(end, start), units = 'hours'))
          } else if(start > start_datetime & end > end_datetime & start < end_datetime){ #if starting time stamp is later than end business hour and ending time stamp is earlier then ending business hour.
            return(as.numeric(difftime(as.POSIXct(paste0(substr(start,1,11), ending_time, ':00')), start), units = 'hours'))
          } else if(start < start_datetime & end < end_datetime & end > start_datetime){ #if starting time stamp is earlier than end business hour and ending time stamp is later than starting business hour.
            return(as.numeric(difftime(end, start_datetime), units = 'hours'))
          } else if(start > end_datetime & end > end_datetime){ #if starting time stamp is later than end business hour and ending time stamp is later than ending business hour.
            return(0)
          } else if(start < start_datetime & end < start_datetime){ #if starting time stamp is earlier than start business hour and ending time stamp is earlier than starting business hour.
            return(0)
          } else {
            return(as.numeric(difftime(end_datetime, start_datetime), units = 'hours'))
          }

        } else { #if starting time stamp and ending time stamp occured on a different day.

          business_hrs <- as.numeric(difftime(as.POSIXct(paste0('2017-01-01', ending_time, ':00')),
                                              as.POSIXct(paste0('2017-01-01', starting_time, ':00')) #calculate business hours range by specified parameters
          ), units = 'hours')

          start_day_hrs <- ifelse(start < as.POSIXct(paste0(substr(start,1,11), ending_time, ':00')) & !as.Date(start) %in% holidays & !format(as.Date(start), "%u") %in% c(6,7), #if start time stamp is earlier than specified ending time
                                  as.numeric(difftime(as.POSIXct(paste0(substr(start,1,11), ending_time, ':00')), start), units = 'hours'), #calculate time between time stamp and specified ending time
                                  0 #else set zero
          ) #calculate amount of time on starting day
          start_day_hrs <- pmin(start_day_hrs, business_hrs) #cap the maximum amount of hours dertermined by the specified business hours
          start_day_hrs
          end_day_hrs <- ifelse(end > as.POSIXct(paste0(substr(end,1,11), starting_time, ':00')) & !as.Date(end) %in% holidays & !format(as.Date(end), "%u") %in% c(6,7), #if end time stamp is later than specified starting time
                                as.numeric(difftime(end, as.POSIXct(paste0(substr(end,1,11), starting_time, ':00'))), units = 'hours'), #calculate time between time stamp and specified starting time
                                0) #calculate amount of time on ending day
          end_day_hrs <- pmin(end_day_hrs, business_hrs) #cap the maximum amount of hours dertermined by the specified business hours
          days_between <- seq(as.Date(start), as.Date(end), by = 1) #create a vector of dates (from and up to including) the starting time stamp and ending time stamp
          business_days <- days_between[!days_between %in% c(as.Date(start), as.Date(end)) & !days_between %in% holidays & !format(as.Date(days_between), "%u") %in% c(6,7)] #remove weekends and holidays from vector of dates

          return(as.numeric(((length(business_days) * business_hrs) + start_day_hrs + end_day_hrs))) #multiply the remaining number of days in the vector (business days) by the amount of business hours and add hours from the starting and end day. Return the result

        }

      }


    })

Answer 2

library(lubridate)

   tickets <- data.frame(open = as.POSIXct(strptime(df$open, "%m/%d/%Y %H:%M")), 
                      closed = as.POSIXct(strptime(df$closed, "%m/%d/%Y %H:%M"))


excludeDayCount <- Vectorize(function(open, close) {

   # Check if the ticket was open and closed on the same day
   if (identical(as.Date(open), as.Date(close))) return (0)

   # All the holidays to be excluded need to be put here
   holidays <- as.POSIXct(strptime(c("12/24/2015", "12/25/2015"), 
                                  "%m/%d/%Y"))

   # Dates between open and close  
   day_seq <- floor_date(seq(open + days(1), close, by = "days"), "day")

   # Count holidays / weekend days
   return(sum(day_seq %in% holidays | wday(day_seq) %in% c(1,7)))

})

bizHrDiff <- function(open, close) {

    # Hours from the end of one work day until the start of another
    hours_between_days <- dhours(6) + dhours(8.5)

    # Number of days to exclude
    excl_days <- excludeDayCount(open, close)  
    # Number of days in include
    reg_days <- as.integer(as.Date(close) - as.Date(open)) - excl_days 



    # Total duration between dates
      span <- as.duration(interval(open, close))
      # Remove the number of holidays and weekends
      span <- span - ddays(excl_days)
      # Remove out of office hours
      span <- span - (reg_days * hours_between_days)




     # Return in hours
      return(time_length(span, unit = "hour"))


}

bizHrDiff(tickets$open, tickets$closed)

Answer 3

I ran into similar needs recently and created a package based on @mvan 's script above. https://github.com/janzzon/difftimeOffice
Input needs to be as POSIX time.
Output is in seconds.
Specify helpdesk open hours by argument working_hours = c(8.5, 18).
Additional holliday days is not implemented (yet).