fix skew autoexplode and add test (#3251)

pola-rs · Apr 28, 2022 · d34d2c2 · d34d2c2
1 parent 4d02a46
commit d34d2c2
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Showing 2 changed files with 25 additions and 1 deletion.
diff --git a/polars/polars-lazy/src/dsl/mod.rs b/polars/polars-lazy/src/dsl/mod.rs
@@ -1489,7 +1489,11 @@ impl Expr {
             move |s| s.skew(bias).map(|opt_v| Series::new(s.name(), &[opt_v])),
             GetOutput::from_type(DataType::Float64),
         )
-        .with_fmt("skew")
+        .with_function_options(|mut options| {
+            options.fmt_str = "skew";
+            options.auto_explode = true;
+            options
+        })
     }
 
     #[cfg(feature = "moment")]

diff --git a/polars/polars-lazy/src/tests/aggregations.rs b/polars/polars-lazy/src/tests/aggregations.rs
@@ -122,6 +122,26 @@ fn test_cumsum_agg_as_key() -> Result<()> {
     Ok(())
 }
 
+#[test]
+fn test_auto_explode() -> Result<()> {
+    let df = fruits_cars();
+
+    let out = df
+        .clone()
+        .lazy()
+        .groupby([col("fruits")])
+        .agg([
+            col("B").skew(false).alias("bskew"),
+            col("B").kurtosis(false, false).alias("bkurt"),
+        ])
+        .collect()?;
+
+    assert!(matches!(out.column("bskew")?.dtype(), DataType::Float64));
+    assert!(matches!(out.column("bkurt")?.dtype(), DataType::Float64));
+
+    Ok(())
+}
+
 #[test]
 fn test_auto_list_agg() -> Result<()> {
     let df = fruits_cars();