How to find next particular day?

Question

I need to find all 'next friday' corresponding to a set of dates.

For instance 2015-08-03 (Monday 3rd, August, 2015) as an input should return 2015-08-07 (Friday 7th, August, 2015) as an output.

I could not find a way to manage this need while reading lubridate's vignette, how would you proceed?

library(lubridate) 
date <- "2015-08-03"
date <- wmd(date)
wday(date, label = TRUE)

Answer 1

Try this function:

nextweekday <- function(date, wday) {
  date <- as.Date(date)
  diff <- wday - wday(date)
  if( diff < 0 )
    diff <- diff + 7
  return(date + diff)
}

You insert your date and the desired wday (Sunday = 1, Monday = 2, ...) and get the result you wanted.