R/time.r

In aaronwolen/activitymonitor: Parse zone files generated by MedAssociates Activity Monitor.

#' Convert MedAssociates time formats to numeric seconds
#' 
#' If \code{use} is "stop", any values not matching the format will produce an error. If \code{use} is "preserve" then unmatched values will be return along with the converted matching values with the original order preserved. If \code{use} is "ignore", values not matching the format will be removed from the result and converted values will be returned as a numeric vector.
#'
#' @param x Character vector of times in the MedAssociates format (e.g., 0000:00.00)
#' @param pattern regular expression pattern used to match time format. A commonly used format is set by default.
#' @param use an optional character string indicating how values not matching the time format pattern should be handled. This must be (an abbreviation) of one of the strings "stop", "preserve" or "ignore". 
#'
#' @return numeric vector of time in seconds.
#'
#' @export

convert_time <- function(x, pattern, use = "stop") {

  if(missing(pattern)) {
    pattern <- "\\d{4}:\\d{2}\\.\\d{2}"
  }

  use <- match.arg(use, c("stop", "preserve", "ignore"))

  matches <- grepl(pattern, x)

  if(use == "stop" & any(!matches)) {
    stop("x doesn't match time pattern.", call. = FALSE)
  }

  # If no matches
  if(!any(matches)) {
    if(use == "ignore") {
      return(NULL)
    } else if(use == "preserve") {
      return(x)
    }
  }

  secs <- calc_seconds(x[matches])

  if(use == "ignore" | !any(!matches)) {
    return(secs)
  } else if (use == "preserve") {
    out <- rep(NA, length(x))
    out[which(!matches)] <- x[which(!matches)]
    out[which(matches)] <- secs
    return(out)
  }
}

#' Calculate seconds from character strings in specified formats

#' @inheritParams convert_time

calc_seconds <- function(x) {
  x <- do.call("rbind", strsplit(x, split = ":"))
  x <- apply(x, 2, as.numeric)
  x <- (x[, 1] * 60) + x[, 2]
  return(x)
}