feat: Add ArrowDataFrame.from_numpy

Author: dangotbanned

narwhals/_arrow/dataframe.py

@@ -53,12 +53,14 @@
     from narwhals._arrow.typing import Mask  # type: ignore[attr-defined]
     from narwhals._arrow.typing import Order  # type: ignore[attr-defined]
     from narwhals.dtypes import DType
+    from narwhals.schema import Schema
     from narwhals.typing import CompliantDataFrame
     from narwhals.typing import CompliantLazyFrame
     from narwhals.typing import SizeUnit
     from narwhals.typing import _1DArray
     from narwhals.typing import _2DArray
     from narwhals.utils import Version
+    from narwhals.utils import _FullContext
 
     JoinType: TypeAlias = Literal[
         "left semi",
@@ -91,6 +93,40 @@ def __init__(
         self._version = version
         validate_backend_version(self._implementation, self._backend_version)
 
+    @classmethod
+    def from_numpy(
+        cls,
+        data: _2DArray,
+        /,
+        *,
+        context: _FullContext,
+        schema: Mapping[str, DType] | Schema | Sequence[str] | None,
+    ) -> Self:
+        from narwhals.schema import Schema
+
+        arrays = [pa.array(val) for val in data.T]
+        if isinstance(schema, (Mapping, Schema)):
+            native = pa.Table.from_arrays(arrays, schema=Schema(schema).to_arrow())
+        elif is_sequence_but_not_str(schema):
+            native = pa.Table.from_arrays(arrays, names=list(schema))
+        elif schema is None:
+            native = pa.Table.from_arrays(
+                arrays, names=[f"column_{x}" for x in range(data.shape[1])]
+            )
+        else:
+            msg = (
+                "`schema` is expected to be one of the following types: "
+                "Mapping[str, DType] | Schema | Sequence[str]. "
+                f"Got {type(schema)}."
+            )
+            raise TypeError(msg)
+        return cls(
+            native,
+            backend_version=context._backend_version,
+            version=context._version,
+            validate_column_names=True,
+        )
+
     def __narwhals_namespace__(self: Self) -> ArrowNamespace:
         from narwhals._arrow.namespace import ArrowNamespace