Remove unnecessary name+unnest(), explain unpack() usage

Author: brookslogan

_casestudies/forecast-covid/forecast-covid.Rmd

@@ -422,6 +422,7 @@ epi_pred_cv_trailing <- epi_slide(
   .ref_time_values = fc_time_values,
   .new_col_name = "fc"
 ) |>
+  # split tibble-type column `fc` into multiple columns with names prefixed by `fc_`:
   unpack(fc, names_sep = "_")
 
 # they match exactly

slides/day1-afternoon.qmd

@@ -2035,10 +2035,8 @@ nowcast_res <- archive |>
   epix_slide(
     .f = lm_mod_pred,
     .before = 14,  # 14-day training period
-    .versions = ref_time_values, 
-    .new_col_name = "res"
+    .versions = ref_time_values
   ) |>
-  unnest() |> # Nesting creates a list-column of data frames; unnesting flattens it back out into regular columns. 
   mutate(targeted_nowcast_date = targeted_nowcast_dates, time_value = actual_nowcast_date) |>
   ungroup()
 
@@ -2425,10 +2423,8 @@ nowcast_res <- archive |>
   epix_slide(
     .f = lm_mod_pred,  # Pass the function defined above
     .before = 30,   # Training period of 30 days
-    .versions = ref_time_values, # Determines the day where training data goes up to (not inclusive)
-    .new_col_name = "res"
+    .versions = ref_time_values # Determines the day where training data goes up to (not inclusive)
   ) |>
-  unnest() |>
   mutate(targeted_nowcast_date = targeted_nowcast_dates,
          time_value = actual_nowcast_date)
 
@@ -2583,4 +2579,4 @@ cowplot::plot_grid(p1, p2)
 
 * Group built [`{rtestim}`](https://dajmcdon.github.io/rtestim) doing for this nonparametrically.
 
-* We may come back to this later...
+* We may come back to this later...