reduced pyarrow dependency: to_numpy

py-polars/polars/eager/series.py

@@ -1814,7 +1814,14 @@ def to_numpy(
         kwargs
             kwargs will be sent to pyarrow.Array.to_numpy
         """
-        return self.to_arrow().to_numpy(*args, zero_copy_only=zero_copy_only, **kwargs)
+        if _PYARROW_AVAILABLE:
+            return self.to_arrow().to_numpy(
+                *args, zero_copy_only=zero_copy_only, **kwargs
+            )
+        else:
+            if self.null_count() == 0:
+                return self.view(ignore_nulls=True)
+            return self._s.to_numpy()
 
     def to_arrow(self) -> "pa.Array":
         """

py-polars/src/series.rs

@@ -215,6 +215,34 @@ impl PySeries {
         Ok(series.into())
     }
 
+
+    /// Should only be called for Series with null types.
+    /// This will cast to floats so that `None = np.nan`
+    pub fn to_numpy(&self, py: Python) -> PyObject {
+        let s = &self.series;
+        if s.bit_repr_is_large() {
+            let s = s.cast(&DataType::Float64).unwrap();
+            let ca = s.f64().unwrap();
+            let np_arr = PyArray1::from_iter(py, ca.into_iter().map(|opt_v| {
+                match opt_v {
+                    Some(v) => v,
+                    None => f64::NAN
+                }
+            }));
+            np_arr.into_py(py)
+        } else {
+            let s = s.cast(&DataType::Float32).unwrap();
+            let ca = s.f32().unwrap();
+            let np_arr = PyArray1::from_iter(py, ca.into_iter().map(|opt_v| {
+                match opt_v {
+                    Some(v) => v,
+                    None => f32::NAN
+                }
+            }));
+            np_arr.into_py(py)
+        }
+    }
+
     pub fn get_object(&self, index: usize) -> PyObject {
         let gil = Python::acquire_gil();
         let python = gil.python();

py-polars/tests/test_series.py

@@ -664,3 +664,11 @@ def test_bitwise():
     out["and"].to_list() == [1, 0, 1]
     out["or"].to_list() == [3, 6, 7]
     out["xor"].to_list() == [2, 6, 6]
+
+
+def test_to_numpy():
+    pl.eager.series._PYARROW_AVAILABLE = False
+    a = pl.Series("a", [1, 2, 3])
+    a.to_numpy() == np.array([1, 2, 3])
+    a = pl.Series("a", [1, 2, None])
+    a.to_numpy() == np.array([1.0, 2.0, np.nan])