Update epi_slide_{sum,mean} examples w/ naming options, cleanup

- Show naming options, including with multi-column selections when we have
  accommodating example data sets
- Select away the pre-existing 7d aggregations in the example data set
- Ungroup output

R/slide.R

@@ -114,6 +114,7 @@
 #'     },
 #'     .window_size = 7
 #'   ) %>%
+#'   ungroup() %>%
 #'   dplyr::select(geo_value, time_value, cases, cases_7sd, cases_7dav)
 #'
 #' # Use the geo_value or the ref_time_value in the slide computation
@@ -605,7 +606,8 @@ get_before_after_from_window <- function(window_size, align, time_type) {
 #' # Compute a 7-day trailing average on cases.
 #' cases_deaths_subset %>%
 #'   group_by(geo_value) %>%
-#'   epi_slide_opt(cases, .f = data.table::frollmean, .window_size = 7)
+#'   epi_slide_opt(cases, .f = data.table::frollmean, .window_size = 7) %>%
+#'   ungroup()
 #'
 #' # Same as above, but adjust `frollmean` settings for speed, accuracy, and
 #' # to allow partially-missing windows.
@@ -615,7 +617,8 @@ get_before_after_from_window <- function(window_size, align, time_type) {
 #'     cases,
 #'     .f = data.table::frollmean, .window_size = 7,
 #'     algo = "exact", hasNA = TRUE, na.rm = TRUE
-#'   )
+#'   ) %>%
+#'   ungroup()
 epi_slide_opt <- function(
     .x, .col_names, .f, ...,
     .window_size = NULL, .align = c("right", "center", "left"),
@@ -919,20 +922,34 @@ epi_slide_opt <- function(
 #'
 #' @export
 #' @examples
-#' # Compute a 7-day trailing average on cases.
-#' cases_deaths_subset %>%
+#' # Compute a 7-day trailing average of case rates.
+#' covid_case_death_rates_extended %>%
 #'   group_by(geo_value) %>%
-#'   epi_slide_mean(cases, .window_size = 7)
+#'   epi_slide_mean(case_rate, .window_size = 7) %>%
+#'   ungroup()
 #'
 #' # Same as above, but adjust `frollmean` settings for speed, accuracy, and
 #' # to allow partially-missing windows.
-#' cases_deaths_subset %>%
+#' covid_case_death_rates_extended %>%
 #'   group_by(geo_value) %>%
 #'   epi_slide_mean(
-#'     cases,
+#'     case_rate,
 #'     .window_size = 7,
 #'     na.rm = TRUE, algo = "exact", hasNA = TRUE
-#'   )
+#'   ) %>%
+#'   ungroup()
+#'
+#' # Compute a 7-day trailing average of case rates and death rates, with custom
+#' # output column names:
+#' covid_case_death_rates_extended %>%
+#'   group_by(geo_value) %>%
+#'   epi_slide_mean(c(case_rate, death_rate), .window_size = 7,
+#'                  .new_col_names = c("smoothed_case_rate", "smoothed_death_rate")) %>%
+#'   ungroup()
+#' covid_case_death_rates_extended %>%
+#'   group_by(geo_value) %>%
+#'   epi_slide_mean(c(case_rate, death_rate), .window_size = 7, .suffix = "_{.n}{.time_unit_abbr}_avg") %>%
+#'   ungroup()
 epi_slide_mean <- function(
     .x, .col_names, ...,
     .window_size = NULL, .align = c("right", "center", "left"),
@@ -995,8 +1012,22 @@ epi_slide_mean <- function(
 #' @examples
 #' # Compute a 7-day trailing sum on cases.
 #' cases_deaths_subset %>%
+#'   select(geo_value, time_value, cases) %>%
+#'   group_by(geo_value) %>%
+#'   epi_slide_sum(cases, .window_size = 7) %>%
+#'   ungroup()
+#'
+#' # Specify output column names and/or naming scheme:
+#' cases_deaths_subset %>%
+#'   select(geo_value, time_value, cases) %>%
+#'   group_by(geo_value) %>%
+#'   epi_slide_sum(cases, .window_size = 7, .new_col_names = "case_sum") %>%
+#'   ungroup()
+#' cases_deaths_subset %>%
+#'   select(geo_value, time_value, cases) %>%
 #'   group_by(geo_value) %>%
-#'   epi_slide_sum(cases, .window_size = 7)
+#'   epi_slide_sum(cases, .window_size = 7, .prefix = "sum_") %>%
+#'   ungroup()
 epi_slide_sum <- function(
     .x, .col_names, ...,
     .window_size = NULL, .align = c("right", "center", "left"),