Fix string column bug in pandas like utils

README.md

@@ -20,6 +20,10 @@ pip install triad
 
 ## Release History
 
+### 0.8.1
+
+* Fixed the [string column issue](https://github.com/fugue-project/fugue/issues/415)
+
 ### 0.8.0
 
 * Support arbitrary column name

tests/utils/test_pandas_like.py

@@ -33,6 +33,9 @@ def test_to_schema():
     df = df.astype(dtype={"x": np.int32, "y": np.dtype("str")})
     assert list(pa.Schema.from_pandas(df)) == list(PD_UTILS.to_schema(df))
 
+    df = pd.Series([], name="col", dtype="string").to_frame()
+    assert list(pa.Schema.from_pandas(df)) == list(PD_UTILS.to_schema(df))
+
     # timestamp test
     df = pd.DataFrame(
         [[datetime(2020, 1, 1, 2, 3, 4, 5), date(2020, 2, 2)]], columns=["a", "b"]

triad/utils/pandas_like.py

@@ -112,7 +112,7 @@ def get_fields() -> Iterable[pa.Field]:
             else:
                 for i in range(df.shape[1]):
                     tp = df.dtypes[i]
-                    if tp == np.dtype("object") or tp == np.dtype(str):
+                    if tp == np.dtype("object") or pd.api.types.is_string_dtype(tp):
                         t = pa.string()
                     else:
                         t = pa.from_numpy_dtype(tp)

triad/utils/pyarrow.py

@@ -134,7 +134,7 @@ def expression_to_schema(expr: str) -> pa.Schema:
     except SyntaxError:
         raise
     except Exception as e:
-        raise SyntaxError(f"Invalid syntax: '{expr}' {str(e)}")
+        raise SyntaxError(f"Invalid syntax: '{expr}' {str(e)}")  # noqa
 
 
 def schema_to_expression(schema: pa.Schema) -> pa.Schema:

triad_version/__init__.py

@@ -1,2 +1,2 @@
 # flake8: noqa
-__version__ = "0.8.0"
+__version__ = "0.8.1"