refactor(python): Update Series.to_numpy to handle Decimal/Time typ…

…es in Rust (#14296)

py-polars/polars/series/series.py

@@ -4358,20 +4358,14 @@ def temporal_dtype_to_numpy(dtype: PolarsDataType) -> Any:
         if (
             use_pyarrow
             and _PYARROW_AVAILABLE
-            and dtype != Object
-            and (dtype == Time or not dtype.is_temporal())
+            and dtype not in (Object, Datetime, Duration, Date)
         ):
             return self.to_arrow().to_numpy(
                 zero_copy_only=zero_copy_only, writable=writable
             )
 
-        if dtype in (Time, Decimal):
-            # There are no native NumPy "time" or "decimal" dtypes
-            raise_no_zero_copy()
-            return np.array(self.to_list(), dtype="object", copy=False)
-
         if self.null_count() == 0:
-            if dtype.is_numeric():
+            if dtype.is_integer() or dtype.is_float():
                 np_array = self._view(ignore_nulls=True)
             elif dtype == Boolean:
                 raise_no_zero_copy()
@@ -4390,7 +4384,7 @@ def temporal_dtype_to_numpy(dtype: PolarsDataType) -> Any:
         else:
             raise_no_zero_copy()
             np_array = self._s.to_numpy()
-            if dtype.is_temporal():
+            if dtype in (Datetime, Duration, Date):
                 np_dtype = temporal_dtype_to_numpy(dtype)
                 np_array = np_array.view(np_dtype)
 

py-polars/src/conversion/chunked_array.rs

@@ -141,16 +141,21 @@ impl ToPyObject for Wrap<&DatetimeChunked> {
 
 impl ToPyObject for Wrap<&TimeChunked> {
     fn to_object(&self, py: Python) -> PyObject {
-        let utils = UTILS.as_ref(py);
-        let convert = utils.getattr(intern!(py, "_to_python_time")).unwrap();
-        let iter = self
-            .0
-            .into_iter()
-            .map(|opt_v| opt_v.map(|v| convert.call1((v,)).unwrap()));
+        let iter = time_to_pyobject_iter(py, self.0);
         PyList::new(py, iter).into_py(py)
     }
 }
 
+pub(crate) fn time_to_pyobject_iter<'a>(
+    py: Python<'a>,
+    ca: &'a TimeChunked,
+) -> impl ExactSizeIterator<Item = Option<&'a PyAny>> {
+    let utils = UTILS.as_ref(py);
+    let convert = utils.getattr(intern!(py, "_to_python_time")).unwrap();
+    ca.0.into_iter()
+        .map(|opt_v| opt_v.map(|v| convert.call1((v,)).unwrap()))
+}
+
 impl ToPyObject for Wrap<&DateChunked> {
     fn to_object(&self, py: Python) -> PyObject {
         let utils = UTILS.as_ref(py);
@@ -165,29 +170,36 @@ impl ToPyObject for Wrap<&DateChunked> {
 
 impl ToPyObject for Wrap<&DecimalChunked> {
     fn to_object(&self, py: Python) -> PyObject {
-        let utils = UTILS.as_ref(py);
-        let convert = utils.getattr(intern!(py, "_to_python_decimal")).unwrap();
-        let py_scale = (-(self.0.scale() as i32)).to_object(py);
-        // if we don't know precision, the only safe bet is to set it to 39
-        let py_precision = self.0.precision().unwrap_or(39).to_object(py);
-        let iter = self.0.into_iter().map(|opt_v| {
-            opt_v.map(|v| {
-                // TODO! use AnyValue so that we have a single impl.
-                const N: usize = 3;
-                let mut buf = [0_u128; N];
-                let n_digits = decimal_to_digits(v.abs(), &mut buf);
-                let buf = unsafe {
-                    std::slice::from_raw_parts(
-                        buf.as_slice().as_ptr() as *const u8,
-                        N * std::mem::size_of::<u128>(),
-                    )
-                };
-                let digits = PyTuple::new(py, buf.iter().take(n_digits));
-                convert
-                    .call1((v.is_negative() as u8, digits, &py_precision, &py_scale))
-                    .unwrap()
-            })
-        });
+        let iter = decimal_to_pyobject_iter(py, self.0);
         PyList::new(py, iter).into_py(py)
     }
 }
+
+pub(crate) fn decimal_to_pyobject_iter<'a>(
+    py: Python<'a>,
+    ca: &'a DecimalChunked,
+) -> impl ExactSizeIterator<Item = Option<&'a PyAny>> {
+    let utils = UTILS.as_ref(py);
+    let convert = utils.getattr(intern!(py, "_to_python_decimal")).unwrap();
+    let py_scale = (-(ca.scale() as i32)).to_object(py);
+    // if we don't know precision, the only safe bet is to set it to 39
+    let py_precision = ca.precision().unwrap_or(39).to_object(py);
+    ca.into_iter().map(move |opt_v| {
+        opt_v.map(|v| {
+            // TODO! use AnyValue so that we have a single impl.
+            const N: usize = 3;
+            let mut buf = [0_u128; N];
+            let n_digits = decimal_to_digits(v.abs(), &mut buf);
+            let buf = unsafe {
+                std::slice::from_raw_parts(
+                    buf.as_slice().as_ptr() as *const u8,
+                    N * std::mem::size_of::<u128>(),
+                )
+            };
+            let digits = PyTuple::new(py, buf.iter().take(n_digits));
+            convert
+                .call1((v.is_negative() as u8, digits, &py_precision, &py_scale))
+                .unwrap()
+        })
+    })
+}

py-polars/src/conversion/mod.rs

@@ -1,5 +1,5 @@
 pub(crate) mod any_value;
-mod chunked_array;
+pub(crate) mod chunked_array;
 
 use std::fmt::{Display, Formatter};
 use std::hash::{Hash, Hasher};

py-polars/src/series/export.rs

@@ -4,6 +4,7 @@ use polars_core::prelude::*;
 use pyo3::prelude::*;
 use pyo3::types::PyList;
 
+use crate::conversion::chunked_array::{decimal_to_pyobject_iter, time_to_pyobject_iter};
 use crate::error::PyPolarsErr;
 use crate::prelude::{ObjectValue, *};
 use crate::{arrow_interop, raise_err, PySeries};
@@ -185,6 +186,12 @@ impl PySeries {
             },
             Date => date_series_to_numpy(py, s),
             Datetime(_, _) | Duration(_) => temporal_series_to_numpy(py, s),
+            Time => {
+                let ca = s.time().unwrap();
+                let iter = time_to_pyobject_iter(py, ca);
+                let np_arr = PyArray1::from_iter(py, iter.map(|v| v.into_py(py)));
+                np_arr.into_py(py)
+            },
             String => {
                 let ca = s.str().unwrap();
                 let np_arr = PyArray1::from_iter(py, ca.into_iter().map(|s| s.into_py(py)));
@@ -200,6 +207,12 @@ impl PySeries {
                 let np_arr = PyArray1::from_iter(py, ca.iter_str().map(|s| s.into_py(py)));
                 np_arr.into_py(py)
             },
+            Decimal(_, _) => {
+                let ca = s.decimal().unwrap();
+                let iter = decimal_to_pyobject_iter(py, ca);
+                let np_arr = PyArray1::from_iter(py, iter.map(|v| v.into_py(py)));
+                np_arr.into_py(py)
+            },
             #[cfg(feature = "object")]
             Object(_, _) => {
                 let ca = s