feat: write_dataset from pylist and pydict (#3527)

Fix this bug from `docs/read_and_write.rst` example:


https://github.com/lancedb/lance/blob/e12bb9eff2a52f753668d4b62c52e4d72b10d294/docs/read_and_write.rst?plain=1#L264

Author: eddyxu

python/python/lance/types.py

@@ -74,6 +74,17 @@ def _coerce_reader(
         and data_obj.__class__.__name__ == "DataFrame"
     ):
         return data_obj.to_arrow().to_reader()
+    elif isinstance(data_obj, dict):
+        batch = pa.RecordBatch.from_pydict(data_obj, schema=schema)
+        return pa.RecordBatchReader.from_batches(batch.schema, [batch])
+    elif (
+        isinstance(data_obj, list)
+        and len(data_obj) > 0
+        and isinstance(data_obj[0], dict)
+    ):
+        # List of dictionaries
+        batch = pa.RecordBatch.from_pylist(data_obj, schema=schema)
+        return pa.RecordBatchReader.from_batches(batch.schema, [batch])
     # for other iterables, assume they are of type Iterable[RecordBatch]
     elif isinstance(data_obj, Iterable):
         if schema is not None:

python/python/tests/test_dataset.py

@@ -2992,3 +2992,22 @@ def test_empty_structs(tmp_path):
     res = ds.take([2, 0, 1])
     assert res.num_rows == 3
     assert res == table.take([2, 0, 1])
+
+
+def test_create_table_from_pylist(tmp_path):
+    data = [
+        {"foo": 1, "bar": "one"},
+        {"foo": 3, "bar": "three"},
+    ]
+    ds = lance.write_dataset(data, tmp_path)
+
+    assert ds.to_table() == pa.Table.from_pylist(data)
+
+
+def test_create_table_from_pydict(tmp_path):
+    dat = {
+        "foo": [1, 3],
+        "bar": ["one", "three"],
+    }
+    ds = lance.write_dataset(dat, tmp_path)
+    assert ds.to_table() == pa.Table.from_pydict(dat)