Changing lubridate function to start on Monday rather than Sunday

Question

dates <- NULL

date <- as.Date("01/01/2014","%d/%m/%Y")

dates <- data.frame(date=as.Date(character())
                    ,cal_day_in_year_num = numeric()
                    ,cal_week_id = numeric()
                    ,cal_week_start_date = as.Date(character())
                    ,cal_week_end_date = as.Date(character())
)

for (i in 1:365) {

  dates[i,1] <- date + days(i-1) ## date

  dates[i,2] <- yday(dates[i,1]) ## cal_day_in_year_num

  dates[i,3] <- paste(year(dates[i,1]),sprintf("%02d",week(dates[i,1])),sep="") ## cal_week_id

  dates[i,4] <- floor_date(dates[i,1], "week") ## cal_week_start_date

  dates[i,5] <- ceiling_date(dates[i,1], "week") ## cal_week_end_date

}

View(dates)

For given dates I'm trying to use the lubridate function to calculate the corresponding start and end dates of the week

The issue I'm having is that lubridate is taking the first day of the week to be Sunday, where as I need it to be Monday - does anyone have a way round this?

Answer 1

You can make your own functions to do this in base. For example,

start.of.week <- function(date)
  date - (setNames(c(6,0:5),0:6) [strftime(date,'%w')])

end.of.week <- function(date)
  date + (setNames(c(0,6:1),0:6) [strftime(date,'%w')])

start.of.week(as.Date(c('2014-01-05','2014-10-02','2014-09-22','2014-09-27')))
# "2013-12-30" "2014-09-29" "2014-09-22" "2014-09-22"
end.of.week(as.Date(c('2014-01-05','2014-10-02','2014-09-22','2014-09-27')))
# "2014-01-05" "2014-10-05" "2014-09-28" "2014-09-28"