REF: change parameter name fname -> path (#30338)

doc/source/user_guide/io.rst

@@ -4763,10 +4763,10 @@ Parquet supports partitioning of data based on the values of one or more columns
 .. ipython:: python
 
     df = pd.DataFrame({'a': [0, 0, 1, 1], 'b': [0, 1, 0, 1]})
-    df.to_parquet(fname='test', engine='pyarrow',
+    df.to_parquet(path='test', engine='pyarrow',
                   partition_cols=['a'], compression=None)
 
-The `fname` specifies the parent directory to which data will be saved.
+The `path` specifies the parent directory to which data will be saved.
 The `partition_cols` are the column names by which the dataset will be partitioned.
 Columns are partitioned in the order they are given. The partition splits are
 determined by the unique values in the partition columns.

doc/source/whatsnew/v1.0.0.rst

@@ -502,7 +502,8 @@ Deprecations
 - :func:`pandas.json_normalize` is now exposed in the top-level namespace.
   Usage of ``json_normalize`` as ``pandas.io.json.json_normalize`` is now deprecated and
   it is recommended to use ``json_normalize`` as :func:`pandas.json_normalize` instead (:issue:`27586`).
--
+- :meth:`DataFrame.to_stata`, :meth:`DataFrame.to_feather`, and :meth:`DataFrame.to_parquet` argument "fname" is deprecated, use "path" instead (:issue:`23574`)
+
 
 .. _whatsnew_1000.prior_deprecations:
 

pandas/core/frame.py

@@ -37,7 +37,12 @@
 
 from pandas._libs import algos as libalgos, lib
 from pandas.compat.numpy import function as nv
-from pandas.util._decorators import Appender, Substitution, rewrite_axis_style_signature
+from pandas.util._decorators import (
+    Appender,
+    Substitution,
+    deprecate_kwarg,
+    rewrite_axis_style_signature,
+)
 from pandas.util._validators import (
     validate_axis_style_args,
     validate_bool_kwarg,
@@ -1829,9 +1834,10 @@ def _from_arrays(cls, arrays, columns, index, dtype=None):
         mgr = arrays_to_mgr(arrays, columns, index, columns, dtype=dtype)
         return cls(mgr)
 
+    @deprecate_kwarg(old_arg_name="fname", new_arg_name="path")
     def to_stata(
         self,
-        fname,
+        path,
         convert_dates=None,
         write_index=True,
         byteorder=None,
@@ -1849,11 +1855,16 @@ def to_stata(
 
         Parameters
         ----------
-        fname : str, buffer or path object
+        path : str, buffer or path object
             String, path object (pathlib.Path or py._path.local.LocalPath) or
             object implementing a binary write() function. If using a buffer
             then the buffer will not be automatically closed after the file
             data has been written.
+
+            .. versionchanged:: 1.0.0
+
+            Previously this was "fname"
+
         convert_dates : dict
             Dictionary mapping columns containing datetime types to stata
             internal format to use when writing the dates. Options are 'tc',
@@ -1927,7 +1938,7 @@ def to_stata(
             kwargs["convert_strl"] = convert_strl
 
         writer = statawriter(
-            fname,
+            path,
             self,
             convert_dates=convert_dates,
             byteorder=byteorder,
@@ -1939,22 +1950,24 @@ def to_stata(
         )
         writer.write_file()
 
-    def to_feather(self, fname):
+    @deprecate_kwarg(old_arg_name="fname", new_arg_name="path")
+    def to_feather(self, path):
         """
         Write out the binary feather-format for DataFrames.
 
         Parameters
         ----------
-        fname : str
+        path : str
             String file path.
         """
         from pandas.io.feather_format import to_feather
 
-        to_feather(self, fname)
+        to_feather(self, path)
 
+    @deprecate_kwarg(old_arg_name="fname", new_arg_name="path")
     def to_parquet(
         self,
-        fname,
+        path,
         engine="auto",
         compression="snappy",
         index=None,
@@ -1973,11 +1986,13 @@ def to_parquet(
 
         Parameters
         ----------
-        fname : str
+        path : str
             File path or Root Directory path. Will be used as Root Directory
             path while writing a partitioned dataset.
 
-            .. versionchanged:: 0.24.0
+            .. versionchanged:: 1.0.0
+
+            Previously this was "fname"
 
         engine : {'auto', 'pyarrow', 'fastparquet'}, default 'auto'
             Parquet library to use. If 'auto', then the option
@@ -2034,7 +2049,7 @@ def to_parquet(
 
         to_parquet(
             self,
-            fname,
+            path,
             engine,
             compression=compression,
             index=index,

pandas/io/feather_format.py

@@ -34,10 +34,11 @@ def to_feather(df: DataFrame, path):
     # raise on anything else as we don't serialize the index
 
     if not isinstance(df.index, Int64Index):
+        typ = type(df.index)
         raise ValueError(
-            "feather does not support serializing {} "
+            f"feather does not support serializing {typ} "
             "for the index; you can .reset_index() "
-            "to make the index into column(s)".format(type(df.index))
+            "to make the index into column(s)"
         )
 
     if not df.index.equals(RangeIndex.from_range(range(len(df)))):
@@ -63,7 +64,7 @@ def to_feather(df: DataFrame, path):
     feather.write_feather(df, path)
 
 
-def read_feather(path, columns=None, use_threads=True):
+def read_feather(path, columns=None, use_threads: bool = True):
     """
     Load a feather-format object from the file path.
 

pandas/io/parquet.py

@@ -46,7 +46,7 @@ def get_engine(engine: str) -> "BaseImpl":
 
 class BaseImpl:
     @staticmethod
-    def validate_dataframe(df):
+    def validate_dataframe(df: DataFrame):
 
         if not isinstance(df, DataFrame):
             raise ValueError("to_parquet only supports IO with DataFrames")
@@ -62,7 +62,7 @@ def validate_dataframe(df):
         if not valid_names:
             raise ValueError("Index level names must be strings")
 
-    def write(self, df, path, compression, **kwargs):
+    def write(self, df: DataFrame, path, compression, **kwargs):
         raise AbstractMethodError(self)
 
     def read(self, path, columns=None, **kwargs):
@@ -80,7 +80,7 @@ def __init__(self):
 
     def write(
         self,
-        df,
+        df: DataFrame,
         path,
         compression="snappy",
         coerce_timestamps="ms",
@@ -137,7 +137,13 @@ def __init__(self):
         self.api = fastparquet
 
     def write(
-        self, df, path, compression="snappy", index=None, partition_cols=None, **kwargs
+        self,
+        df: DataFrame,
+        path,
+        compression="snappy",
+        index=None,
+        partition_cols=None,
+        **kwargs,
     ):
         self.validate_dataframe(df)
         # thriftpy/protocol/compact.py:339:
@@ -196,9 +202,9 @@ def read(self, path, columns=None, **kwargs):
 
 
 def to_parquet(
-    df,
+    df: DataFrame,
     path,
-    engine="auto",
+    engine: str = "auto",
     compression="snappy",
     index: Optional[bool] = None,
     partition_cols=None,
@@ -209,6 +215,7 @@ def to_parquet(
 
     Parameters
     ----------
+    df : DataFrame
     path : str
         File path or Root Directory path. Will be used as Root Directory path
         while writing a partitioned dataset.
@@ -255,7 +262,7 @@ def to_parquet(
     )
 
 
-def read_parquet(path, engine="auto", columns=None, **kwargs):
+def read_parquet(path, engine: str = "auto", columns=None, **kwargs):
     """
     Load a parquet object from the file path, returning a DataFrame.