Add missing changes from pandas-devgh-21868

Author: gfyoung

doc/source/whatsnew/v0.24.0.txt

@@ -383,6 +383,7 @@ Deprecations
 - :meth:`MultiIndex.to_hierarchical` is deprecated and will be removed in a future version  (:issue:`21613`)
 - :meth:`Series.ptp` is deprecated. Use ``numpy.ptp`` instead (:issue:`21614`)
 - :meth:`Series.compress` is deprecated. Use ``Series[condition]`` instead (:issue:`18262`)
+- The signature in :meth:`Series.to_csv` has been deprecated. Please follow the signature in :meth:`DataFrame.to_csv` instead (:issue:`19715`)
 
 .. _whatsnew_0240.prior_deprecations:
 

pandas/core/series.py

@@ -3764,19 +3764,25 @@ def from_csv(cls, path, sep=',', parse_dates=True, header=None,
         return result
 
     def to_csv(self, *args, **kwargs):
-        names = ['path_or_buf', 'sep', 'na_rep', 'float_format', 'columns',
-                 'header', 'index', 'index_label', 'mode', 'encoding',
-                 'compression', 'quoting', 'quotechar', 'line_terminator',
-                 'chunksize', 'tupleize_cols', 'date_format', 'doublequote',
-                 'escapechar', 'decimal']
-
-        old_names = ['path_or_buf', 'index', 'sep', 'na_rep', 'float_format',
-                     'header', 'index_label', 'mode', 'encoding',
-                     'compression', 'date_format', 'decimal']
-
-        if 'path' in kwargs:
-            warnings.warn("Argument 'path' is now named 'path_or_buf'")
-            kwargs['path_or_buf'] = kwargs.pop('path')
+        warning_klass = FutureWarning
+        stack_level = 2
+
+        names = ["path_or_buf", "sep", "na_rep", "float_format", "columns",
+                 "header", "index", "index_label", "mode", "encoding",
+                 "compression", "quoting", "quotechar", "line_terminator",
+                 "chunksize", "tupleize_cols", "date_format", "doublequote",
+                 "escapechar", "decimal"]
+
+        old_names = ["path_or_buf", "index", "sep", "na_rep", "float_format",
+                     "header", "index_label", "mode", "encoding",
+                     "compression", "date_format", "decimal"]
+
+        if "path" in kwargs:
+            warnings.warn("The signature of `Series.to_csv` was aligned "
+                          "to that of `DataFrame.to_csv`, and argument "
+                          "'path' will be renamed to 'path_or_buf'.",
+                          warning_klass, stacklevel=stack_level)
+            kwargs["path_or_buf"] = kwargs.pop("path")
 
         if len(args) > 1:
             # Either "index" (old signature) or "sep" (new signature) is being
@@ -3785,7 +3791,7 @@ def to_csv(self, *args, **kwargs):
 
             if not (is_string_like(maybe_sep) and len(maybe_sep) == 1):
                 # old signature
-                warnings.warn("The signature of `Series.to_csv` was  aligned "
+                warnings.warn("The signature of `Series.to_csv` was aligned "
                               "to that of `DataFrame.to_csv`. Note that the "
                               "order of arguments changed, and the new one "
                               "has 'sep' in first place, for which \"{}\" is "
@@ -3794,7 +3800,7 @@ def to_csv(self, *args, **kwargs):
                               "to the documentation for `DataFrame.to_csv` "
                               "when updating your function "
                               "calls.".format(maybe_sep),
-                              FutureWarning, stacklevel=2)
+                              warning_klass, stacklevel=stack_level)
                 names = old_names
 
         pos_args = dict(zip(names[:len(args)], args))
@@ -3805,11 +3811,14 @@ def to_csv(self, *args, **kwargs):
                                  "({})".format(key, names.index(key)))
             kwargs[key] = pos_args[key]
 
-        if kwargs.get('header', None) is None:
-            warnings.warn("Argument 'header' has changed default value to "
+        if kwargs.get("header", None) is None:
+            warnings.warn("The signature of `Series.to_csv` was aligned "
+                          "to that of `DataFrame.to_csv`, and argument "
+                          "'header' will change its default value to "
                           "True: please pass an explicit value to suppress "
-                          "this warning")
-
+                          "this warning.", warning_klass,
+                          stacklevel=stack_level)
+            kwargs["header"] = False  # Backwards compatibility.
         return self.to_frame().to_csv(**kwargs)
 
     # This entire method is going to be removed, so the shared docstring

pandas/tests/frame/test_to_csv.py

@@ -893,22 +893,27 @@ def test_to_csv_line_terminators(self):
 
     def test_to_csv_from_csv_categorical(self):
 
-        # CSV with categoricals should result in the same output as when one
-        # would add a "normal" Series/DataFrame.
-        s = Series(pd.Categorical(['a', 'b', 'b', 'a', 'a', 'c', 'c', 'c']))
-        s2 = Series(['a', 'b', 'b', 'a', 'a', 'c', 'c', 'c'])
+        # CSV with categoricals should result in the same output
+        # as when one would add a "normal" Series/DataFrame.
+        s = Series(pd.Categorical(["a", "b", "b", "a", "a", "c", "c", "c"]))
+        s2 = Series(["a", "b", "b", "a", "a", "c", "c", "c"])
         res = StringIO()
-        s.to_csv(res)
+
+        s.to_csv(res, header=False)
         exp = StringIO()
-        s2.to_csv(exp)
+
+        s2.to_csv(exp, header=False)
         assert res.getvalue() == exp.getvalue()
 
         df = DataFrame({"s": s})
         df2 = DataFrame({"s": s2})
+
         res = StringIO()
         df.to_csv(res)
+
         exp = StringIO()
         df2.to_csv(exp)
+
         assert res.getvalue() == exp.getvalue()
 
     def test_to_csv_path_is_none(self):

pandas/tests/series/test_io.py

@@ -45,6 +45,24 @@ def test_from_csv_deprecation(self):
                 depr_ts = Series.from_csv(path)
                 assert_series_equal(depr_ts, ts)
 
+    @pytest.mark.parametrize("arg", ["path", "header", "both"])
+    def test_to_csv_deprecation(self, arg):
+        # see gh-19715
+        with ensure_clean() as path:
+            if arg == "path":
+                kwargs = dict(path=path, header=False)
+            elif arg == "header":
+                kwargs = dict(path_or_buf=path)
+            else:  # Both discrepancies match.
+                kwargs = dict(path=path)
+
+            with tm.assert_produces_warning(FutureWarning):
+                self.ts.to_csv(**kwargs)
+
+                # Make sure roundtrip still works.
+                ts = self.read_csv(path)
+                assert_series_equal(self.ts, ts, check_names=False)
+
     def test_from_csv(self):
 
         with ensure_clean() as path:

pandas/tests/test_common.py

@@ -2,6 +2,7 @@
 
 import pytest
 import os
+import warnings
 import collections
 from functools import partial
 
@@ -14,6 +15,14 @@
 import pandas.util.testing as tm
 
 
+def catch_to_csv_depr():
+    # Catching warnings because Series.to_csv has
+    # been deprecated. Remove this context when
+    # Series.to_csv has been aligned.
+
+    return warnings.catch_warnings(record=True)
+
+
 def test_get_callable_name():
     getname = com.get_callable_name
 
@@ -122,11 +131,12 @@ def test_standardize_mapping():
 def test_compression_size(obj, method, compression_only):
 
     with tm.ensure_clean() as filename:
-        getattr(obj, method)(filename, compression=compression_only)
-        compressed = os.path.getsize(filename)
-        getattr(obj, method)(filename, compression=None)
-        uncompressed = os.path.getsize(filename)
-        assert uncompressed > compressed
+        with catch_to_csv_depr():
+            getattr(obj, method)(filename, compression=compression_only)
+            compressed = os.path.getsize(filename)
+            getattr(obj, method)(filename, compression=None)
+            uncompressed = os.path.getsize(filename)
+            assert uncompressed > compressed
 
 
 @pytest.mark.parametrize('obj', [
@@ -139,16 +149,21 @@ def test_compression_size_fh(obj, method, compression_only):
 
     with tm.ensure_clean() as filename:
         f, _handles = _get_handle(filename, 'w', compression=compression_only)
-        with f:
-            getattr(obj, method)(f)
-            assert not f.closed
-        assert f.closed
-        compressed = os.path.getsize(filename)
+
+        with catch_to_csv_depr():
+            with f:
+                getattr(obj, method)(f)
+                assert not f.closed
+            assert f.closed
+            compressed = os.path.getsize(filename)
+
     with tm.ensure_clean() as filename:
         f, _handles = _get_handle(filename, 'w', compression=None)
-        with f:
-            getattr(obj, method)(f)
-            assert not f.closed
+
+        with catch_to_csv_depr():
+            with f:
+                getattr(obj, method)(f)
+                assert not f.closed
         assert f.closed
         uncompressed = os.path.getsize(filename)
         assert uncompressed > compressed