feat: introduce epix_as_of_current() for convenience

NAMESPACE

@@ -76,6 +76,7 @@ export(epi_slide_mean)
 export(epi_slide_opt)
 export(epi_slide_sum)
 export(epix_as_of)
+export(epix_as_of_current)
 export(epix_fill_through_version)
 export(epix_merge)
 export(epix_slide)
@@ -99,6 +100,7 @@ export(new_epi_df)
 export(relocate)
 export(rename)
 export(revision_summary)
+export(set_versions_end)
 export(slice)
 export(sum_groups_epi_df)
 export(time_column_names)

R/grouped_epi_archive.R

@@ -437,9 +437,13 @@ epix_slide.grouped_epi_archive <- function(
   out <- lapply(.versions, function(.version) {
     # Ungrouped as-of data; `epi_df` if `all_versions` is `FALSE`,
     # `epi_archive` if `all_versions` is `TRUE`:
+    min_time_value <- .version - .before
+    if (is.na(min_time_value)) {
+      min_time_value <- -Inf
+    }
     as_of_raw <- .x$private$ungrouped %>% epix_as_of(
       .version,
-      min_time_value = .version - .before,
+      min_time_value = min_time_value,
       all_versions = .all_versions
     )
 

R/methods-epi_archive.R

@@ -58,6 +58,7 @@
 #' epix_as_of(archive_cases_dv_subset2, max(archive_cases_dv_subset$DT$version))
 #'
 #' @importFrom data.table between key
+#' @importFrom checkmate assert_scalar assert_logical assert_class
 #' @export
 epix_as_of <- function(x, version, min_time_value = -Inf, all_versions = FALSE,
                        max_version = deprecated()) {
@@ -88,6 +89,14 @@ epix_as_of <- function(x, version, min_time_value = -Inf, all_versions = FALSE,
   if (version > x$versions_end) {
     cli_abort("`version` must be at most `epi_archive$versions_end`.")
   }
+  assert_scalar(min_time_value, na.ok = FALSE)
+  min_time_value_inf <- is.infinite(min_time_value) && min_time_value < 0
+  min_time_value_same_type <- typeof(min_time_value) == typeof(x$DT$time_value) &
+    class(min_time_value) == class(x$DT$time_value)
+  if (!min_time_value_inf && !min_time_value_same_type) {
+    cli_abort("`min_time_value` must be either -Inf or a time_value of the same type and
+      class as `epi_archive$time_value`.")
+  }
   assert_logical(all_versions, len = 1)
   if (!is.na(x$clobberable_versions_start) && version >= x$clobberable_versions_start) {
     cli_warn(
@@ -100,39 +109,63 @@ epix_as_of <- function(x, version, min_time_value = -Inf, all_versions = FALSE,
     )
   }
 
-  # We can't disable nonstandard evaluation nor use the `..` feature in the `i`
-  # argument of `[.data.table` below; try to avoid problematic names and abort
-  # if we fail to do so:
-  .min_time_value <- min_time_value
-  .version <- version
-  if (any(c(".min_time_value", ".version") %in% names(x$DT))) {
-    cli_abort("epi_archives can't contain a `.min_time_value` or `.version` column")
-  }
-
   # Filter by version and return
   if (all_versions) {
     # epi_archive is copied into result, so we can modify result directly
     result <- epix_truncate_versions_after(x, version)
-    result$DT <- result$DT[time_value >= .min_time_value, ] # nolint: object_usage_linter
+    if (!min_time_value_inf) {
+      # See below for why we need this branch.
+      filter_mask <- result$DT$time_value >= min_time_value
+      result$DT <- result$DT[filter_mask, ] # nolint: object_usage_linter
+    }
     return(result)
   }
 
   # Make sure to use data.table ways of filtering and selecting
-  as_of_epi_df <- x$DT[time_value >= .min_time_value & version <= .version, ] %>% # nolint: object_usage_linter
-    unique(
-      by = c("geo_value", "time_value", other_keys),
-      fromLast = TRUE
-    ) %>%
+  if (min_time_value_inf) {
+    # This branch is needed for `epix_as_of` to work with `yearmonth` time type
+    # to avoid time_value > .min_time_value, which is NA for `yearmonth`.
+    filter_mask <- x$DT$version <= version
+  } else {
+    filter_mask <- x$DT$time_value >= min_time_value & x$DT$version <= version
+  }
+  as_of_epi_df <- x$DT[filter_mask, ] %>%
+    unique(by = c("geo_value", "time_value", other_keys), fromLast = TRUE) %>%
+    as.data.frame() %>%
     tibble::as_tibble() %>%
     dplyr::select(-"version") %>%
-    as_epi_df(
-      as_of = version,
-      other_keys = other_keys
-    )
+    as_epi_df(as_of = version, other_keys = other_keys)
 
   return(as_of_epi_df)
 }
 
+#' Get the latest snapshot from an `epi_archive` object.
+#'
+#' The latest snapshot is the snapshot of the last known version.
+#'
+#' @param x An `epi_archive` object
+#' @return The latest snapshot from an `epi_archive` object
+#' @export
+epix_as_of_current <- function(x) {
+  assert_class(x, "epi_archive")
+  x %>% epix_as_of(.$versions_end)
+}
+
+#' Set the `versions_end` attribute of an `epi_archive` object
+#'
+#' An escape hatch for epix_as_of, which does not allow version >
+#' `$versions_end`.
+#'
+#' @param x An `epi_archive` object
+#' @param versions_end The new `versions_end` value
+#' @return An `epi_archive` object with the updated `versions_end` attribute
+#' @export
+set_versions_end <- function(x, versions_end) {
+  assert_class(x, "epi_archive")
+  validate_version_bound(versions_end, x$DT, na_ok = FALSE)
+  x$versions_end <- versions_end
+  x
+}
 
 #' Fill `epi_archive` unobserved history
 #'
@@ -880,10 +913,13 @@ epix_slide.epi_archive <- function(
 #' @noRd
 epix_slide_versions_default <- function(ea) {
   versions_with_updates <- c(ea$DT$version, ea$versions_end)
-  tidyr::full_seq(versions_with_updates, guess_period(versions_with_updates))
+  if (ea$time_type == "yearmonth") {
+    min(versions_with_updates) + seq(0, max(versions_with_updates) - min(versions_with_updates), by = 1)
+  } else {
+    tidyr::full_seq(versions_with_updates, guess_period(versions_with_updates))
+  }
 }
 
-
 #' Filter an `epi_archive` object to keep only older versions
 #'
 #' Generates a filtered `epi_archive` from an `epi_archive` object, keeping

R/slide.R

@@ -1108,7 +1108,7 @@ epi_slide_sum <- function(
 #' `before` and `after` args are assumed to have been validated by the calling
 #' function (using `validate_slide_window_arg`).
 #'
-#' @importFrom checkmate assert_function
+#' @importFrom checkmate assert_function anyInfinite
 #' @keywords internal
 full_date_seq <- function(x, before, after, time_type) {
   if (!time_type %in% c("day", "week", "yearmonth", "integer")) {
@@ -1126,7 +1126,7 @@ full_date_seq <- function(x, before, after, time_type) {
   if (time_type %in% c("yearmonth", "integer")) {
     all_dates <- seq(min(x$time_value), max(x$time_value), by = 1L)
 
-    if (before != 0 && before != Inf) {
+    if (before != 0 && !anyInfinite(before)) {
       pad_early_dates <- all_dates[1L] - before:1
     }
     if (after != 0) {
@@ -1139,7 +1139,7 @@ full_date_seq <- function(x, before, after, time_type) {
     )
 
     all_dates <- seq(min(x$time_value), max(x$time_value), by = by)
-    if (before != 0 && before != Inf) {
+    if (before != 0 && !anyInfinite(before)) {
       # The behavior is analogous to the branch with tsibble types above. For
       # more detail, note that the function `seq.Date(from, ..., length.out =
       # n)` returns `from + 0:n`. Since we want `from + 1:n`, we drop the first

_pkgdown.yml

@@ -76,11 +76,13 @@ reference:
     desc: Functions operating on `epi_archive` objects.
   - contents:
       - epix_as_of
+      - epix_as_of_current
       - epix_slide
       - epix_merge
       - revision_summary
       - epix_fill_through_version
       - epix_truncate_versions_after
+      - set_versions_end
 
   - title: Basic analysis and visualization
   - contents:

tests/testthat/test-methods-epi_archive.R

@@ -128,3 +128,40 @@ test_that("group_vars works as expected", {
     "geo_value"
   )
 })
+
+test_that("epix_as_of_now works as expected", {
+  expect_equal(
+    attr(ea2_data %>% as_epi_archive() %>% epix_as_of_current(), "metadata")$as_of,
+    as.Date("2020-06-04")
+  )
+  time_value <- as.Date("2020-06-01")
+  df <- dplyr::tribble(
+    ~geo_value, ~time_value, ~version, ~cases,
+    "ca", time_value, time_value, 1,
+    "ca", time_value + 7, time_value + 7, 2,
+  )
+  expect_equal(
+    attr(df %>% as_epi_archive() %>% epix_as_of_current(), "metadata")$as_of,
+    as.Date("2020-06-08")
+  )
+  time_value <- tsibble::yearmonth(as.Date("2020-06-01") - lubridate::month(1))
+  df <- dplyr::tribble(
+    ~geo_value, ~time_value, ~version, ~cases,
+    "ca", time_value, time_value, 1,
+    "ca", time_value + lubridate::month(1), time_value + lubridate::month(1), 2,
+  )
+  expect_equal(
+    attr(df %>% as_epi_archive() %>% epix_as_of_current(), "metadata")$as_of,
+    tsibble::yearmonth("2020-06")
+  )
+  time_value <- 2020
+  df <- dplyr::tribble(
+    ~geo_value, ~time_value, ~version, ~cases,
+    "ca", time_value, time_value, 1,
+    "ca", time_value + 7, time_value + 7, 2,
+  )
+  expect_equal(
+    attr(df %>% as_epi_archive() %>% epix_as_of_current(), "metadata")$as_of,
+    2027
+  )
+})