categorical aggregation output consistency

pola-rs · Sep 20, 2021 · cd81f5e · cd81f5e
1 parent fec76cf
commit cd81f5e
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Showing 9 changed files with 516 additions and 35 deletions.
diff --git a/polars/polars-core/src/chunked_array/ops/aggregate.rs b/polars/polars-core/src/chunked_array/ops/aggregate.rs
@@ -346,11 +346,11 @@ impl VarAggSeries for BooleanChunked {
 #[cfg(feature = "dtype-categorical")]
 impl VarAggSeries for CategoricalChunked {
     fn var_as_series(&self) -> Series {
-        self.cast::<UInt32Type>().unwrap().var_as_series()
+        unimplemented!()
     }
 
     fn std_as_series(&self) -> Series {
-        self.cast::<UInt32Type>().unwrap().std_as_series()
+        unimplemented!()
     }
 }
 impl VarAggSeries for ListChunked {

diff --git a/polars/polars-core/src/chunked_array/ops/mod.rs b/polars/polars-core/src/chunked_array/ops/mod.rs
@@ -803,6 +803,17 @@ impl ChunkFullNull for ListChunked {
     }
 }
 
+#[cfg(feature = "dtype-categorical")]
+impl ChunkFullNull for CategoricalChunked {
+    fn full_null(name: &str, length: usize) -> CategoricalChunked {
+        use crate::chunked_array::builder::CategoricalChunkedBuilder;
+        let mut builder = CategoricalChunkedBuilder::new(name, length);
+        let iter = (0..length).map(|_| None);
+        builder.from_iter(iter);
+        builder.finish()
+    }
+}
+
 impl ListChunked {
     fn full_null_with_dtype(name: &str, length: usize, dt: &DataType) -> ListChunked {
         let mut builder = get_list_builder(dt, 0, length, name);

diff --git a/polars/polars-core/src/chunked_array/ops/unique/mod.rs b/polars/polars-core/src/chunked_array/ops/unique/mod.rs
@@ -308,9 +308,7 @@ impl ChunkUnique<CategoricalType> for CategoricalChunked {
     }
     #[cfg(feature = "mode")]
     fn mode(&self) -> Result<Self> {
-        let mut ca = self.cast::<UInt32Type>()?.mode()?;
-        ca.categorical_map = self.categorical_map.clone();
-        ca.cast()
+        Ok(ChunkFullNull::full_null(self.name(), 1))
     }
 }