R/time.r

In aaronwolen/ralfred: Analyze your Alfred usage.

#' Convert timestamp to POSIXct format
#' 
#' @param x Vector of raw timestamps
#' @importFrom lubridate seconds ymd_hms with_tz
convert_timestamp <- function(x) {
  with_tz(
    seconds(x) + ymd_hms("2000-01-01 00:00:00", quiet = TRUE), 
    format(Sys.time(), "%Z"))
}

#' Adjust UTC times relative to current time zone
#' 
#' @param x POSIXct dates to be converted
#' @param hours a positive or negative integer indicating how many hours the
#'   times should be adjusted
#' @export
#' @importFrom lubridate hours
adjust_times <- function(x, hours) {
  stopifnot(is(x, "POSIXct"))
  x + hours(hours)
}


#' Pretty hour labels
#' 
#' Extracts hours element from a date-time object and returns an ordered factor
#' ranging from 12a to 11pm.
#' 
#' @param x date-time object
#' 

pretty_hour <- function(x) {
  x <- format(x, "%l%p")
  x <- factor(tolower(sub("M", "", sub("^\\s", "", x))),
    levels = paste0(c(12, 1:12, 1:11), rep(c("a", "p"), each = 12)))
  return(x) 
}