dragosmg commented on code in PR #13196:
URL: https://github.com/apache/arrow/pull/13196#discussion_r879435840
##########
r/R/dplyr-datetime-helpers.R:
##########
@@ -201,19 +213,130 @@ build_formats <- function(orders) {
}
build_format_from_order <- function(order) {
- year_chars <- c("%y", "%Y")
- month_chars <- c("%m", "%B", "%b")
- day_chars <- "%d"
-
- outcome <- switch(
- order,
- "ymd" = expand.grid(year_chars, month_chars, day_chars),
- "ydm" = expand.grid(year_chars, day_chars, month_chars),
- "mdy" = expand.grid(month_chars, day_chars, year_chars),
- "myd" = expand.grid(month_chars, year_chars, day_chars),
- "dmy" = expand.grid(day_chars, month_chars, year_chars),
- "dym" = expand.grid(day_chars, year_chars, month_chars)
+ char_list <- list(
+ "y" = c("%y", "%Y"),
+ "m" = c("%m", "%B", "%b"),
+ "d" = "%d",
+ "H" = "%H",
+ "M" = "%M",
+ "S" = "%S"
+ )
+
+ split_order <- strsplit(order, split = "")[[1]]
+
+ outcome <- expand.grid(char_list[split_order])
+ formats_with_sep <- do.call(paste, c(outcome, sep = "-"))
+ formats_without_sep <- do.call(paste, c(outcome, sep = ""))
+ c(formats_with_sep, formats_without_sep)
+}
+
+process_data_for_parsing <- function(x,
+ orders) {
+
+ processed_x <- x$cast(string())
+
+ # make all separators (non-letters and non-numbers) into "-"
+ processed_x <- call_binding("gsub", "[^A-Za-z0-9]", "-", processed_x)
+ # collapse multiple separators into a single one
+ processed_x <- call_binding("gsub", "-{2,}", "-", processed_x)
+
+ # we need to transform `x` when orders are `ym`, `my`, and `yq`
+ # for `ym` and `my` orders we add a day ("01")
+ augmented_x_ym <- NULL
+ if (any(orders %in% c("ym", "my"))) {
+ # add day as "-01" if there is a "-" separator and as "01" if not
+ augmented_x_ym <- call_binding(
+ "if_else",
+ call_binding("grepl", "-", processed_x),
+ call_binding("paste0", processed_x, "-01"),
+ call_binding("paste0", processed_x, "01")
+ )
+ }
+
+ # for `yq` we need to transform the quarter into the start month (lubridate
+ # behaviour) and then add 01 to parse to the first day of the quarter
+ augmented_x_yq <- NULL
+ if (any(orders == "yq")) {
+ # extract everything that comes after the `-` separator, i.e. the quarter
+ # (e.g. 4 from 2022-4)
+ quarter_x <- call_binding("gsub", "^.*?-", "", processed_x)
+ # we should probably error if quarter is not in 1:4
+ # extract everything that comes before the `-`, i.e. the year (e.g. 2002
+ # in 2002-4)
+ year_x <- call_binding("gsub", "-.*$", "", processed_x)
+ quarter_x <- quarter_x$cast(int32())
+ month_x <- (quarter_x - 1) * 3 + 1
+ augmented_x_yq <- call_binding("paste0", year_x, "-", month_x, "-01")
+ }
+
+ list(
+ "augmented_x_ym" = augmented_x_ym,
+ "augmented_x_yq" = augmented_x_yq,
+ "processed_x" = processed_x
+ )
+}
+
+attempt_parsing <- function(x,
+ orders,
+ formats = NULL) {
+ if (is.null(formats)) {
+ # this is the situation in which orders were passed with `exact = TRUE`
+ # no data processing takes place
+ # we don't derive formats as the orders are assumed to be formats
+ parse_attempt_expressions <- build_strptime_exps(x, orders)
+ return(parse_attempt_expressions)
+ }
+
+ processed_data <- process_data_for_parsing(x, orders)
+
+ processed_x <- processed_data[["processed_x"]]
+ augmented_x_ym <- processed_data[["augmented_x_ym"]]
+ augmented_x_yq <- processed_data[["augmented_x_yq"]]
+
+ # build a list of expressions for each format
+ parse_attempt_exp_processed_x <- build_strptime_exps(processed_x, formats)
+
+ # build separate expression lists of parsing attempts for the orders that
+ # need an augmented `x`
+ # list for attempts when orders %in% c("ym", "my")
+ parse_attempt_exp_augmented_x_ym <- list()
+
+ if (!is.null(augmented_x_ym)) {
+ parse_attempt_exp_augmented_x_ym <- build_strptime_exps(augmented_x_ym,
formats)
+ }
+
+ # list for attempts when orders %in% c("yq")
+ parse_attempt_exp_augmented_x_yq <- list()
+ if (!is.null(augmented_x_yq)) {
+ parse_attempt_exp_augmented_x_yq <- build_strptime_exps(augmented_x_yq,
formats)
+ }
+
+ # combine all attempts expressions in prep for coalesce
+ # if the users passes only a short order (`ym`, `my` or `yq`) then only use
+ # the corresponding augmented_x
+ if (all(orders == "ym") || all(orders == "my")) {
+ parse_attempt_expressions <- parse_attempt_exp_augmented_x_ym
+ } else if (all(orders == "yq")) {
+ parse_attempt_expressions <- parse_attempt_exp_augmented_x_yq
+ } else {
+ parse_attempt_expressions <- c(
+ # if we have an augmented x give preference to the corresponding
+ # parsing attempts
+ parse_attempt_exp_augmented_x_ym,
+ parse_attempt_exp_augmented_x_yq,
+ parse_attempt_exp_processed_x
+ )
+ }
+ parse_attempt_expressions
+}
Review Comment:
Done.
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