Excel time to numeric (#479)

Add excel_time_to_numeric to convert many time formats to seconds

---------

Co-authored-by: Sam Firke <[email protected]>
Co-authored-by: olivroy <[email protected]>

NAMESPACE

@@ -8,6 +8,11 @@ S3method(clean_names,tbl_graph)
 S3method(clean_names,tbl_lazy)
 S3method(describe_class,default)
 S3method(describe_class,factor)
+S3method(excel_time_to_numeric,POSIXct)
+S3method(excel_time_to_numeric,POSIXlt)
+S3method(excel_time_to_numeric,character)
+S3method(excel_time_to_numeric,logical)
+S3method(excel_time_to_numeric,numeric)
 S3method(fisher.test,default)
 S3method(fisher.test,tabyl)
 S3method(print,tabyl)
@@ -34,6 +39,7 @@ export(convert_to_datetime)
 export(crosstab)
 export(describe_class)
 export(excel_numeric_to_date)
+export(excel_time_to_numeric)
 export(find_header)
 export(fisher.test)
 export(get_dupes)

NEWS.md

@@ -12,6 +12,8 @@ These are all minor breaking changes resulting from enhancements and are not exp
 
 * `row_to_names()` now accepts multiple rows as input, and merges them using a new `sep` argument (#536). The default is `sep = "_"`. When handling multiple `NA` values, `row_to_names()` ignores them and only merges non-NA values for column names. When all values are `NA`, `row_to_names()` creates a column name of `"NA"`, a character, rather than `NA`.
 
+* The new function `excel_time_to_numeric()` converts times from Excel that do not have accompanying dates into a number of seconds.  (#245, thanks to **@billdenney** for the feature.)
+
 ## Bug fixes
 
 * `adorn_totals("row")` now succeeds if the new `name` of the totals row is already a factor level of the input data.frame (#529, thanks @egozoglu for reporting).

R/excel_dates.R

@@ -33,6 +33,7 @@
 #'   https://support.microsoft.com/en-us/help/2722715/support-for-the-leap-second).
 #'
 #' @export
+#' @seealso \code{\link{excel_time_to_numeric}}
 #' @examples
 #' excel_numeric_to_date(40000)
 #' excel_numeric_to_date(40000.5) # No time is included

R/excel_time_to_numeric.R

@@ -0,0 +1,166 @@
+#' Convert a time that may be inconsistently or inconveniently formatted from
+#' Microsoft Excel to a numeric number of seconds between 0 and 86400.
+#'
+#' @details
+#'
+#' `time_value` may be one of the following formats:
+#' \itemize{
+#'   \item{numeric}{The input must be a value from 0 to 1 (exclusive of 1); this value is returned as-is.}
+#'   \item{POSIXlt or POSIXct}{The input must be on the day 1899-12-31 (any other day will cause an error).  The time of day is extracted and converted to a fraction of a day.}
+#'   \item{character}{Any of the following (or a mixture of the choices):}
+#'   \itemize{
+#'     \item{A character string that is a number between 0 and 1 (exclusive of 1).  This value will be converted like a numeric value.}
+#'     \item{A character string that looks like a date on 1899-12-31 (specifically, it must start with `"1899-12-31 "`), converted like a POSIXct object as described above.}
+#'     \item{A character string that looks like a time.  Choices are 12-hour time as hour, minute, and optionally second followed by "am" or "pm" (case insensitive) or 24-hour time when hour, minute, optionally second, and no "am" or "pm" is included.}
+#'   }
+#' }
+#'
+#' @param time_value A vector of values to convert (see Details)
+#' @param round_seconds Should the output number of seconds be rounded to an
+#'   integer?
+#' @return A vector of numbers >= 0 and <86400
+#' @family Date-time cleaning
+#' @seealso `\link{excel_numeric_to_date}`
+#' @export
+excel_time_to_numeric <- function(time_value, round_seconds = TRUE) {
+  UseMethod("excel_time_to_numeric")
+}
+
+#' @export
+excel_time_to_numeric.logical <- function(time_value, round_seconds = TRUE) {
+  if (all(is.na(time_value))) {
+    rep(NA_real_, length(time_value))
+  } else {
+    stop("If given as a logical vector, all values must be ")
+  }
+}
+
+#' @export
+excel_time_to_numeric.numeric <- function(time_value, round_seconds = TRUE) {
+  if (all(is.na(time_value) |
+    (time_value >= 0 &
+      time_value < 1))) {
+    seconds <- time_value * 86400
+    if (round_seconds) {
+      seconds <- round(seconds)
+    }
+  } else {
+    stop("When numeric, all `time_value`s must be between 0 and 1 (exclusive of 1)")
+  }
+  seconds
+}
+
+#' @export
+excel_time_to_numeric.POSIXct <- function(time_value, round_seconds = TRUE) {
+  # using trunc removes timezone inconsistency.  Timezones aren't used in Excel.
+  seconds <- as.numeric(time_value) - as.numeric(trunc(time_value, units = "days"))
+  mask_good_seconds <- is.na(seconds) | (seconds >= 0 & seconds < 86400)
+  if (all(mask_good_seconds)) {
+    if (round_seconds) {
+      seconds <- round(seconds)
+    }
+  } else {
+    # This should be impossible except for leap seconds
+    stop(sum(!mask_good_seconds), " `time_value`s were not at or above 0 and below 86400.") # nocov
+  }
+  seconds
+}
+
+#' @export
+excel_time_to_numeric.POSIXlt <- function(time_value, round_seconds = TRUE) {
+  excel_time_to_numeric.POSIXct(
+    as.POSIXct(time_value),
+    round_seconds = round_seconds
+  )
+}
+
+#' @export
+excel_time_to_numeric.character <- function(time_value, round_seconds = TRUE) {
+  ret <- rep(NA_real_, length(time_value))
+  patterns <-
+    list(
+      number = "^0(\\.[0-9]*)?$",
+      # SI numbers have to have the form [number]E-[number] becasue the number
+      # has to be between 0 and 1 and can't be bigger than 1.
+      si_number = "^[1-9](\\.[0-9]*)?E-[0-9]+$",
+      "12hr" = "^([0]?[1-9]|1[0-2]):([0-5][0-9])(?::([0-5][0-9]))? ?([AP]M)$",
+      "24hr" = "^([0-1]?[0-9]|2[0-3]):([0-5][0-9])(?::([0-5][0-9]))?$",
+      # The ".*?" at the end of POSIX is to allow for a time zone, but it allows
+      #   for imperfect parsing if there were just a date and a space.
+      # The entire time is optional to allow for midnight which shows as
+      #   just the date and time zone.
+      POSIX = "1899-12-31 (?:([0-1]?[0-9]|2[0-3]):([0-5][0-9])(?::([0-5][0-9]))?)?.*?$"
+    )
+  mask_na <- is.na(time_value)
+  mask_number <-
+    grepl(pattern = patterns$number, x = time_value) |
+      grepl(pattern = patterns$si_number, x = time_value)
+  mask_POSIX <- grepl(pattern = patterns[["POSIX"]], x = time_value)
+  mask_12hr <- grepl(pattern = patterns[["12hr"]], x = time_value, ignore.case = TRUE)
+  mask_24hr <- grepl(pattern = patterns[["24hr"]], x = time_value)
+  unmatched <- !(mask_na | mask_number | mask_POSIX | mask_12hr | mask_24hr)
+  if (any(unmatched)) {
+    stop(
+      "The following character strings did not match an interpretable ",
+      "character format for time conversion: ",
+      paste(unique(time_value[unmatched]))
+    )
+  }
+  if (any(mask_number)) {
+    ret[mask_number] <-
+      excel_time_to_numeric.numeric(
+        time_value = as.numeric(time_value[mask_number]),
+        round_seconds = round_seconds
+      )
+  }
+  mask_clock <- mask_12hr | mask_24hr | mask_POSIX
+  if (any(mask_clock)) {
+    hours <- minutes <- seconds <- rep(NA_real_, length(time_value))
+    if (any(mask_POSIX)) {
+      hours[mask_POSIX] <-
+        gsub(pattern = patterns$POSIX, replacement = "\\1", x = time_value[mask_POSIX])
+      minutes[mask_POSIX] <-
+        gsub(pattern = patterns$POSIX, replacement = "\\2", x = time_value[mask_POSIX])
+      seconds[mask_POSIX] <-
+        gsub(pattern = patterns$POSIX, replacement = "\\3", x = time_value[mask_POSIX])
+    }
+    if (any(mask_12hr)) {
+      mask_pm <- rep(FALSE, length(time_value))
+      hours[mask_12hr] <-
+        gsub(pattern = patterns[["12hr"]], replacement = "\\1", x = time_value[mask_12hr], ignore.case = TRUE)
+      minutes[mask_12hr] <-
+        gsub(pattern = patterns[["12hr"]], replacement = "\\2", x = time_value[mask_12hr], ignore.case = TRUE)
+      seconds[mask_12hr] <-
+        gsub(pattern = patterns[["12hr"]], replacement = "\\3", x = time_value[mask_12hr], ignore.case = TRUE)
+      # 12 is 0 hours in the AM and the PM conversion below adds the needed 12
+      # at noon.
+      mask_0_hours <- mask_12hr & (hours %in% "12")
+      hours[mask_0_hours] <- "0"
+      mask_pm[mask_12hr] <-
+        tolower(
+          gsub(pattern = patterns[["12hr"]], replacement = "\\4", x = time_value[mask_12hr], ignore.case = TRUE)
+        ) %in% "pm"
+      hours[mask_pm] <- 12 + as.numeric(hours[mask_pm])
+    }
+    if (any(mask_24hr)) {
+      hours[mask_24hr] <-
+        gsub(pattern = patterns[["24hr"]], replacement = "\\1", x = time_value[mask_24hr])
+      minutes[mask_24hr] <-
+        gsub(pattern = patterns[["24hr"]], replacement = "\\2", x = time_value[mask_24hr])
+      seconds[mask_24hr] <-
+        gsub(pattern = patterns[["24hr"]], replacement = "\\3", x = time_value[mask_24hr])
+    }
+    hours[hours %in% ""] <- "0"
+    minutes[minutes %in% ""] <- "0"
+    seconds[seconds %in% ""] <- "0"
+
+    ret[mask_clock] <-
+      as.numeric(hours[mask_clock]) * 3600 +
+      as.numeric(minutes[mask_clock]) * 60 +
+      as.numeric(seconds[mask_clock])
+  }
+  if (round_seconds) {
+    ret <- round(ret)
+  }
+  ret
+}