From ad9c8a8c8bc3f1d63cfebb61e21f1c967ae7685e Mon Sep 17 00:00:00 2001
From: Etienne Bacher <52219252+etiennebacher@users.noreply.github.com>
Date: Tue, 2 Apr 2024 13:18:02 +0200
Subject: [PATCH 1/5] init

---
 R/extendr-wrappers.R   | 2 ++
 R/series__series.R     | 8 +++++---
 src/rust/src/series.rs | 6 ++++++
 3 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/R/extendr-wrappers.R b/R/extendr-wrappers.R
index 90723eab9..718e1e4fd 100644
--- a/R/extendr-wrappers.R
+++ b/R/extendr-wrappers.R
@@ -1324,6 +1324,8 @@ RPolarsSeries$set_sorted_mut <- function(descending) invisible(.Call(wrap__RPola
 
 RPolarsSeries$struct_fields <- function() .Call(wrap__RPolarsSeries__struct_fields, self)
 
+RPolarsSeries$struct_unnest <- function() .Call(wrap__RPolarsSeries__struct_unnest, self)
+
 RPolarsSeries$from_arrow_array_stream_str <- function(name, robj_str) .Call(wrap__RPolarsSeries__from_arrow_array_stream_str, name, robj_str)
 
 RPolarsSeries$from_arrow_array_robj <- function(name, array) .Call(wrap__RPolarsSeries__from_arrow_array_robj, name, array)
diff --git a/R/series__series.R b/R/series__series.R
index 5c3e615c6..9bc1adbee 100644
--- a/R/series__series.R
+++ b/R/series__series.R
@@ -270,7 +270,11 @@ Series_struct = method_as_active_binding(
       self, expr_struct_make_sub_ns,
       fields = method_as_active_binding(function() {
         unwrap(.pr$Series$struct_fields(pl_series), "in $struct$fields:")
-      })
+      }),
+      unnest = function() {
+        .pr$Series$struct_unnest(pl_series) |>
+          unwrap("in $struct$unnest():")
+      }
     )
   }
 )
@@ -1101,8 +1105,6 @@ Series_item = function(index = NULL) {
 #'
 #' s$clear(n = 5)
 Series_clear = function(n = 0) {
-  # TODO: check whether n < 0 should be removed when resolved upstream
-  # https://github.com/pola-rs/polars/issues/15421
   if (length(n) > 1 || !is.numeric(n) || n < 0) {
     Err_plain("`n` must be an integer greater or equal to 0.") |>
       unwrap("in $clear():")
diff --git a/src/rust/src/series.rs b/src/rust/src/series.rs
index 212690912..b6aed6729 100644
--- a/src/rust/src/series.rs
+++ b/src/rust/src/series.rs
@@ -505,6 +505,12 @@ impl RPolarsSeries {
         Ok(ca.fields().iter().map(|s| s.name()).collect())
     }
 
+    fn struct_unnest(&self) -> RResult<RPolarsDataFrame> {
+        let ca = self.0.struct_().map_err(polars_to_rpolars_err)?;
+        let out: pl::DataFrame = ca.clone().into();
+        Ok(out.into())
+    }
+
     pub fn from_arrow_array_stream_str(name: Robj, robj_str: Robj) -> RResult<Robj> {
         let name = robj_to!(str, name)?;
         let s = crate::arrow_interop::to_rust::arrow_stream_to_series_internal(robj_str)?

From 8a10f525511d873c6617faceab601bfb624956f7 Mon Sep 17 00:00:00 2001
From: Etienne Bacher <52219252+etiennebacher@users.noreply.github.com>
Date: Tue, 2 Apr 2024 13:30:55 +0200
Subject: [PATCH 2/5] tests, docs

---
 NEWS.md                                 |  1 +
 R/series__series.R                      |  8 ++++++++
 man/Series_struct_unnest.Rd             | 21 +++++++++++++++++++++
 tests/testthat/_snaps/after-wrappers.md |  9 +++++----
 tests/testthat/test-series.R            | 14 ++++++++++++++
 5 files changed, 49 insertions(+), 4 deletions(-)
 create mode 100644 man/Series_struct_unnest.Rd

diff --git a/NEWS.md b/NEWS.md
index ac08d3b75..2e607dd3b 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -114,6 +114,7 @@
 - New methods `$select_seq()` and `$with_columns_seq()` for `DataFrame` and
   `LazyFrame` (#1003).
 - New method `$clear()` for `DataFrame`, `LazyFrame`, and `Series` (#1004).
+- New method `$struct$unnest()` for `Series` (#1010).
 
 ### Bug fixes
 
diff --git a/R/series__series.R b/R/series__series.R
index 9bc1adbee..f0525019b 100644
--- a/R/series__series.R
+++ b/R/series__series.R
@@ -271,6 +271,14 @@ Series_struct = method_as_active_binding(
       fields = method_as_active_binding(function() {
         unwrap(.pr$Series$struct_fields(pl_series), "in $struct$fields:")
       }),
+      #' Convert this struct Series to a DataFrame with a separate column for
+      #' each field
+      #'
+      #' @name Series_struct_unnest
+      #' @return A DataFrame
+      #' @examples
+      #' s = pl$Series(values = c(1, 2), dtype = pl$Struct(foo = pl$Float64))
+      #' s$struct$unnest()
       unnest = function() {
         .pr$Series$struct_unnest(pl_series) |>
           unwrap("in $struct$unnest():")
diff --git a/man/Series_struct_unnest.Rd b/man/Series_struct_unnest.Rd
new file mode 100644
index 000000000..7b4cb4c3b
--- /dev/null
+++ b/man/Series_struct_unnest.Rd
@@ -0,0 +1,21 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/series__series.R
+\name{Series_struct_unnest}
+\alias{Series_struct_unnest}
+\alias{Series_struct}
+\title{Convert this struct Series to a DataFrame with a separate column for
+each field}
+\usage{
+Series_struct()
+}
+\value{
+A DataFrame
+}
+\description{
+Convert this struct Series to a DataFrame with a separate column for
+each field
+}
+\examples{
+s = pl$Series(values = c(1, 2), dtype = pl$Struct(foo = pl$Float64))
+s$struct$unnest()
+}
diff --git a/tests/testthat/_snaps/after-wrappers.md b/tests/testthat/_snaps/after-wrappers.md
index 4a8581ab8..3e0a1bdc1 100644
--- a/tests/testthat/_snaps/after-wrappers.md
+++ b/tests/testthat/_snaps/after-wrappers.md
@@ -717,10 +717,11 @@
       [37] "rep"                         "set_sorted_mut"             
       [39] "shape"                       "sleep"                      
       [41] "sort_mut"                    "std"                        
-      [43] "struct_fields"               "sub"                        
-      [45] "sum"                         "to_fmt_char"                
-      [47] "to_frame"                    "to_r"                       
-      [49] "value_counts"                "var"                        
+      [43] "struct_fields"               "struct_unnest"              
+      [45] "sub"                         "sum"                        
+      [47] "to_fmt_char"                 "to_frame"                   
+      [49] "to_r"                        "value_counts"               
+      [51] "var"                        
 
 # public and private methods of each class RThreadHandle
 
diff --git a/tests/testthat/test-series.R b/tests/testthat/test-series.R
index b7a887db4..225251410 100644
--- a/tests/testthat/test-series.R
+++ b/tests/testthat/test-series.R
@@ -679,3 +679,17 @@ test_that("$clear() works", {
     "greater or equal to 0"
   )
 })
+
+test_that("$struct$unnest() works", {
+  s = pl$Series(values = c(1, 2), dtype = pl$Struct(foo = pl$Float64))
+  expect_identical(
+    s$struct$unnest()$to_list(),
+    list(foo = c(1, 2))
+  )
+  # empty Series
+  s = pl$Series(dtype = pl$Struct(foo = pl$Float64))
+  expect_identical(
+    s$struct$unnest()$to_list(),
+    list(foo = numeric(0))
+  )
+})

From 581bc795d25abe62a9f3ee84be99fb01c5feb2d2 Mon Sep 17 00:00:00 2001
From: Etienne Bacher <52219252+etiennebacher@users.noreply.github.com>
Date: Tue, 2 Apr 2024 13:34:34 +0200
Subject: [PATCH 3/5] one additional test

---
 tests/testthat/test-series.R | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/tests/testthat/test-series.R b/tests/testthat/test-series.R
index 225251410..3f5035114 100644
--- a/tests/testthat/test-series.R
+++ b/tests/testthat/test-series.R
@@ -686,10 +686,20 @@ test_that("$struct$unnest() works", {
     s$struct$unnest()$to_list(),
     list(foo = c(1, 2))
   )
+
   # empty Series
   s = pl$Series(dtype = pl$Struct(foo = pl$Float64))
   expect_identical(
     s$struct$unnest()$to_list(),
     list(foo = numeric(0))
   )
+
+  # Series "name" param is not used, only pl$Struct() name is used
+  s = pl$Series(name = "bar", dtype = pl$Struct(pl$Float64))
+  expected = list(numeric(0))
+  names(expected) = ""
+  expect_identical(
+    s$struct$unnest()$to_list(),
+    expected
+  )
 })

From f7709fc026f61310b11db466c2f8de1e3d029472 Mon Sep 17 00:00:00 2001
From: Etienne Bacher <52219252+etiennebacher@users.noreply.github.com>
Date: Tue, 2 Apr 2024 13:36:33 +0200
Subject: [PATCH 4/5] udpate test

---
 tests/testthat/test-series.R | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/tests/testthat/test-series.R b/tests/testthat/test-series.R
index 3f5035114..b9044122f 100644
--- a/tests/testthat/test-series.R
+++ b/tests/testthat/test-series.R
@@ -695,11 +695,9 @@ test_that("$struct$unnest() works", {
   )
 
   # Series "name" param is not used, only pl$Struct() name is used
-  s = pl$Series(name = "bar", dtype = pl$Struct(pl$Float64))
-  expected = list(numeric(0))
-  names(expected) = ""
+  s = pl$Series(name = "bar", dtype = pl$Struct(foo = pl$Float64))
   expect_identical(
     s$struct$unnest()$to_list(),
-    expected
+    list(foo = numeric(0))
   )
 })

From dae6a58669384cc1e9e53efb28482c1c5395d570 Mon Sep 17 00:00:00 2001
From: Etienne Bacher <52219252+etiennebacher@users.noreply.github.com>
Date: Wed, 10 Apr 2024 13:54:01 +0200
Subject: [PATCH 5/5] fix usage section

---
 R/series__series.R          | 2 ++
 man/Series_struct_unnest.Rd | 2 +-
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/R/series__series.R b/R/series__series.R
index 55cab0008..a41f23687 100644
--- a/R/series__series.R
+++ b/R/series__series.R
@@ -274,6 +274,8 @@ Series_struct = method_as_active_binding(
       #' Convert this struct Series to a DataFrame with a separate column for
       #' each field
       #'
+      #' @usage Series_struct_unnest()
+      #'
       #' @name Series_struct_unnest
       #' @return A DataFrame
       #' @examples
diff --git a/man/Series_struct_unnest.Rd b/man/Series_struct_unnest.Rd
index 7b4cb4c3b..d836c20f6 100644
--- a/man/Series_struct_unnest.Rd
+++ b/man/Series_struct_unnest.Rd
@@ -6,7 +6,7 @@
 \title{Convert this struct Series to a DataFrame with a separate column for
 each field}
 \usage{
-Series_struct()
+Series_struct_unnest()
 }
 \value{
 A DataFrame