add 'has_validity' method

polars/polars-arrow/src/array/mod.rs

@@ -1,7 +1,7 @@
 pub mod default_arrays;
 
 use crate::utils::CustomIterTools;
-use arrow::array::{ArrayRef, BooleanArray, ListArray, PrimitiveArray, Utf8Array};
+use arrow::array::{Array, ArrayRef, BooleanArray, ListArray, PrimitiveArray, Utf8Array};
 use arrow::bitmap::MutableBitmap;
 use arrow::buffer::MutableBuffer;
 use arrow::datatypes::DataType;
@@ -171,3 +171,11 @@ pub trait ListFromIter {
     }
 }
 impl ListFromIter for ListArray<i64> {}
+
+pub trait PolarsArray: Array {
+    fn has_validity(&self) -> bool {
+        self.validity().is_some()
+    }
+}
+
+impl<A: Array> PolarsArray for A {}

polars/polars-core/src/chunked_array/mod.rs

@@ -196,10 +196,18 @@ impl<T> ChunkedArray<T> {
     }
 
     /// Get the buffer of bits representing null values
+    #[inline]
     pub fn iter_validities(&self) -> impl Iterator<Item = Option<&Bitmap>> + '_ {
         self.chunks.iter().map(|arr| arr.validity())
     }
 
+    #[inline]
+    /// Return if any the chunks in this `[ChunkedArray]` have a validity bitmap.
+    /// no bitmap means no null values.
+    pub fn has_validity(&self) -> bool {
+        self.iter_validities().any(|valid| valid.is_some())
+    }
+
     /// Shrink the capacity of this array to fit it's length.
     pub fn shrink_to_fit(&mut self) {
         self.chunks = vec![arrow::compute::concat::concatenate(

polars/polars-core/src/chunked_array/ops/take/take_random.rs

@@ -141,7 +141,7 @@ where
         if self.chunks.len() == 1 {
             let arr = chunks.next().unwrap();
 
-            if self.null_count() == 0 {
+            if !self.has_validity() {
                 let t = NumTakeRandomCont {
                     slice: arr.values(),
                 };

polars/polars-core/src/series/implementations/boolean.rs

@@ -322,6 +322,10 @@ impl SeriesTrait for SeriesWrap<BooleanChunked> {
         self.0.null_count()
     }
 
+    fn has_validity(&self) -> bool {
+        self.0.has_validity()
+    }
+
     fn unique(&self) -> Result<Series> {
         ChunkUnique::unique(&self.0).map(|ca| ca.into_series())
     }

polars/polars-core/src/series/implementations/categorical.rs

@@ -301,6 +301,10 @@ impl SeriesTrait for SeriesWrap<CategoricalChunked> {
         self.0.null_count()
     }
 
+    fn has_validity(&self) -> bool {
+        self.0.has_validity()
+    }
+
     fn unique(&self) -> Result<Series> {
         ChunkUnique::unique(&self.0).map(|ca| ca.into_series())
     }

polars/polars-core/src/series/implementations/dates_time.rs

@@ -484,6 +484,10 @@ macro_rules! impl_dyn_series {
                 self.0.null_count()
             }
 
+            fn has_validity(&self) -> bool {
+                self.0.has_validity()
+            }
+
             fn unique(&self) -> Result<Series> {
                 self.0.unique().map(|ca| ca.$into_logical().into_series())
             }

polars/polars-core/src/series/implementations/floats.rs

@@ -467,6 +467,10 @@ macro_rules! impl_dyn_series {
                 self.0.null_count()
             }
 
+            fn has_validity(&self) -> bool {
+                self.0.has_validity()
+            }
+
             fn unique(&self) -> Result<Series> {
                 ChunkUnique::unique(&self.0).map(|ca| ca.into_series())
             }

polars/polars-core/src/series/implementations/list.rs

@@ -244,6 +244,10 @@ impl SeriesTrait for SeriesWrap<ListChunked> {
         self.0.null_count()
     }
 
+    fn has_validity(&self) -> bool {
+        self.0.has_validity()
+    }
+
     fn is_null(&self) -> BooleanChunked {
         self.0.is_null()
     }

polars/polars-core/src/series/implementations/mod.rs

@@ -628,6 +628,10 @@ macro_rules! impl_dyn_series {
                 self.0.null_count()
             }
 
+            fn has_validity(&self) -> bool {
+                self.0.has_validity()
+            }
+
             fn unique(&self) -> Result<Series> {
                 ChunkUnique::unique(&self.0).map(|ca| ca.into_series())
             }

polars/polars-core/src/series/implementations/object.rs

@@ -185,6 +185,10 @@ where
         ObjectChunked::null_count(&self.0)
     }
 
+    fn has_validity(&self) -> bool {
+        ObjectChunked::has_validity(&self.0)
+    }
+
     fn unique(&self) -> Result<Series> {
         ChunkUnique::unique(&self.0).map(|ca| ca.into_series())
     }

polars/polars-core/src/series/implementations/utf8.rs

@@ -314,6 +314,10 @@ impl SeriesTrait for SeriesWrap<Utf8Chunked> {
         self.0.null_count()
     }
 
+    fn has_validity(&self) -> bool {
+        self.0.has_validity()
+    }
+
     fn unique(&self) -> Result<Series> {
         ChunkUnique::unique(&self.0).map(|ca| ca.into_series())
     }

polars/polars-core/src/series/series_trait.rs

@@ -677,6 +677,10 @@ pub trait SeriesTrait:
         invalid_operation_panic!(self)
     }
 
+    /// Return if any the chunks in this `[ChunkedArray]` have a validity bitmap.
+    /// no bitmap means no null values.
+    fn has_validity(&self) -> bool;
+
     /// Get unique values in the Series.
     fn unique(&self) -> Result<Series> {
         invalid_operation!(self)