Calculate the number of weekdays between 2 dates in R

Question

I\'m trying to write an R function to calculate the number of weekdays between two dates. For example, Nweekdays(\'01/30/2011\',\'02/04/2011\') would equal 5.

Simila

Answer 1

I use the following approach - first a helper:

weekDays <- function(UPPER = TRUE) {
    days <- c('MONDAY', 'TUESDAY', 'WEDNESDAY',
      'THURSDAY', 'FRIDAY', 'SATURDAY', 
      'SUNDAY')
    if(!UPPER) return(.Internal(tolower(days))) 
    days
}

... and now the main function:

NumWeekDays <- function(dd, Xdays = c('saturday', 'sunday')) {
    # a function to count the number of non-Xdays in a month
    # >
    # first check if Xdays is of correct format
    stopifnot( all(.Internal(tolower(Xdays)) %in% weekDays(UP = FALSE)))
    # >
    # a helper function to find the number of non-X days between two dates
    NonXDays <- function(startDate, endDate, Xdays) {
        sum(!(.Internal(tolower(weekdays(seq(startDate, endDate, 'day')))) %in% 
              .Internal(tolower(Xdays))))
    }
    startDate <- as.Date(as.yearmon(index(dd)), frac = 0)
    endDate <- as.Date(as.yearmon(index(dd)), frac = 1)
    vapply(1:nrow(dd), 
           FUN = function(i) NonXDays(startDate[i], 
                                      endDate[i], 
                                      Xdays = c('saturday', 'sunday')), 
           FUN.VALUE = numeric(1))
}

Example:

set.seed(1)
dx <- apply.monthly(xts(rnorm(600), order.by = Sys.Date() + 1:600), mean)

R> NumWeekDays(dx)
 [1] 23 21 22 23 20 23 22 20 22 22 21 22 23 21 22 22 21 23 21 21