fix: Keeps Enum order when converting to R

DESCRIPTION

@@ -35,6 +35,7 @@ Suggests:
     nanoarrow (>= 0.6.0),
     nycflights13,
     patrick,
+    quickcheck,
     pillar,
     rlang,
     rmarkdown,
@@ -116,7 +117,7 @@ Collate:
     'sql.R'
     'vctrs.R'
     'zzz.R'
-Config/rextendr/version: 0.3.1
+Config/rextendr/version: 0.3.1.9000
 VignetteBuilder: knitr
 Config/polars/LibVersion: 0.43.0
 Config/polars/RustToolchainVersion: nightly-2024-09-19

NEWS.md

@@ -5,6 +5,7 @@
 ## Polars R Package 0.20.0
 
 - Updated rust-polars to 0.43.1 (#1230).
+- Maintains level order when converting Enums to factors (#1252, @andyquinterom)
 
 ### Breaking changes
 

src/rust/src/conversion_s_to_r.rs

@@ -110,9 +110,11 @@ pub fn pl_series_to_list(
                     .set_class(["rpolars_raw_list", "list"])
                     .expect("this class label is always valid")
             }),
-            Enum(_, _) => s
-                .categorical()
-                .map(|ca| extendr_api::call!("factor", ca.iter_str().collect_robj()).unwrap()),
+            Enum(_, _) => s.categorical().map(|ca| {
+                let levels = ca.unique().unwrap().iter_str().collect_robj();
+                let values = ca.iter_str().collect_robj();
+                extendr_api::call!("factor", values, levels).unwrap()
+            }),
             Categorical(_, _) => s
                 .categorical()
                 .map(|ca| extendr_api::call!("factor", ca.iter_str().collect_robj()).unwrap()),