group_nest

NAMESPACE

@@ -20,6 +20,7 @@ S3method(group_indices,duckplyr_df)
 S3method(group_keys,duckplyr_df)
 S3method(group_map,duckplyr_df)
 S3method(group_modify,duckplyr_df)
+S3method(group_nest,duckplyr_df)
 S3method(group_size,duckplyr_df)
 S3method(group_vars,duckplyr_df)
 S3method(groups,duckplyr_df)
@@ -257,6 +258,7 @@ importFrom(dplyr,group_indices)
 importFrom(dplyr,group_keys)
 importFrom(dplyr,group_map)
 importFrom(dplyr,group_modify)
+importFrom(dplyr,group_nest)
 importFrom(dplyr,group_rows)
 importFrom(dplyr,group_size)
 importFrom(dplyr,group_split)

R/duckplyr-package.R

@@ -10,6 +10,7 @@
 #' @importFrom collections queue
 #' @importFrom dplyr group_by_prepare
 #' @importFrom dplyr group_indices
+#' @importFrom dplyr group_nest
 #' @importFrom dplyr group_split
 #' @importFrom dplyr grouped_df
 #' @importFrom dplyr if_else

R/group_nest.R

@@ -0,0 +1,36 @@
+# Generated by 02-duckplyr_df-methods.R
+#' @export
+group_nest.duckplyr_df <- function(.tbl, ..., .key = "data", keep = FALSE) {
+  # Our implementation
+  rel_try(
+    # Always fall back to dplyr
+    "No relational implementation for group_nest()" = TRUE,
+    {
+      return(out)
+    }
+  )
+
+  # dplyr forward
+  group_nest <- dplyr$group_nest.data.frame
+  out <- group_nest(.tbl, ..., .key = .key, keep = keep)
+  return(out)
+
+  # dplyr implementation
+  if (dots_n(...)) {
+    group_nest_impl(group_by(.tbl, ...), .key = .key, keep = keep)
+  } else {
+    tibble(!!.key := list(.tbl))
+  }
+}
+
+duckplyr_group_nest <- function(.tbl, ...) {
+  try_fetch(
+    .tbl <- as_duckplyr_df(.tbl),
+    error = function(e) {
+      testthat::skip(conditionMessage(e))
+    }
+  )
+  out <- group_nest(.tbl, ...)
+  class(out) <- setdiff(class(out), "duckplyr_df")
+  out
+}

R/overwrite.R

@@ -20,6 +20,7 @@ methods_overwrite <- function() {
   vctrs::s3_register("dplyr::group_keys", "data.frame", group_keys.duckplyr_df)
   vctrs::s3_register("dplyr::group_map", "data.frame", group_map.duckplyr_df)
   vctrs::s3_register("dplyr::group_modify", "data.frame", group_modify.duckplyr_df)
+  vctrs::s3_register("dplyr::group_nest", "data.frame", group_nest.duckplyr_df)
   vctrs::s3_register("dplyr::group_size", "data.frame", group_size.duckplyr_df)
   vctrs::s3_register("dplyr::group_vars", "data.frame", group_vars.duckplyr_df)
   vctrs::s3_register("dplyr::groups", "data.frame", groups.duckplyr_df)

R/restore.R

@@ -20,6 +20,7 @@ methods_restore <- function() {
   vctrs::s3_register("dplyr::group_keys", "data.frame", dplyr$group_keys.data.frame)
   vctrs::s3_register("dplyr::group_map", "data.frame", dplyr$group_map.data.frame)
   vctrs::s3_register("dplyr::group_modify", "data.frame", dplyr$group_modify.data.frame)
+  vctrs::s3_register("dplyr::group_nest", "data.frame", dplyr$group_nest.data.frame)
   vctrs::s3_register("dplyr::group_size", "data.frame", dplyr$group_size.data.frame)
   vctrs::s3_register("dplyr::group_vars", "data.frame", dplyr$group_vars.data.frame)
   vctrs::s3_register("dplyr::groups", "data.frame", dplyr$groups.data.frame)

dplyr-methods/group_nest.txt

@@ -0,0 +1,7 @@
+group_nest.data.frame <- function(.tbl, ..., .key = "data", keep = FALSE) {
+  if (dots_n(...)) {
+    group_nest_impl(group_by(.tbl, ...), .key = .key, keep = keep)
+  } else {
+    tibble(!!.key := list(.tbl))
+  }
+}

tests/testthat/test-as_duckplyr_df.R

@@ -834,6 +834,22 @@ test_that("as_duckplyr_df() and group_modify(~ .x)", {
   expect_equal(pre, post)
 })
 
+test_that("as_duckplyr_df() and group_nest()", {
+  withr::local_envvar(DUCKPLYR_FORCE = "FALSE")
+
+  skip("Always returns tibble")
+
+  # Data
+  test_df <- data.frame(a = 1:6 + 0, b = 2, g = rep(1:3, 1:3))
+
+  # Run
+  pre <- test_df %>% as_duckplyr_df() %>% group_nest()
+  post <- test_df %>% group_nest() %>% as_duckplyr_df()
+
+  # Compare
+  expect_equal(pre, post)
+})
+
 test_that("as_duckplyr_df() and group_size()", {
   withr::local_envvar(DUCKPLYR_FORCE = "FALSE")
 

tools/00-funs.R

@@ -16,7 +16,7 @@ df_methods <-
   filter(!grepl("_$|^as[.]tbl$", name)) %>%
   # special dplyr methods, won't implement
   filter(!(name %in% c(
-    "group_nest", "group_split", "group_trim", "n_groups",
+    "group_split", "group_trim", "n_groups",
     "same_src", # data frames can be copied into duck-frames with zero cost
     NULL
   ))) %>%
@@ -30,6 +30,7 @@ df_methods <-
     "group_keys",
     "group_map",
     "group_modify",
+    "group_nest",
     "group_size",
     "groups",
     "rowwise",