Backport PR pandas-dev#36937 on branch 1.1.x: BUG: GH36928 Allow dict_keys to be used as column names by read_csv

Author: abmyii

doc/source/whatsnew/v1.1.4.rst

@@ -14,6 +14,7 @@ including other versions of pandas.
 
 Fixed regressions
 ~~~~~~~~~~~~~~~~~
+- Fixed regression in :func:`read_csv` raising a ``ValueError`` when ``names`` was of type ``dict_keys`` (:issue:`36928`)
 - Fixed regression where attempting to mutate a :class:`DateOffset` object would no longer raise an ``AttributeError`` (:issue:`36940`)
 - Fixed regression where :meth:`DataFrame.agg` would fail with :exc:`TypeError` when passed positional arguments to be passed on to the aggregation function (:issue:`36948`).
 - Fixed regression in :class:`RollingGroupby` with ``sort=False`` not being respected (:issue:`36889`)

pandas/io/parsers.py

@@ -413,7 +413,9 @@ def _validate_names(names):
     if names is not None:
         if len(names) != len(set(names)):
             raise ValueError("Duplicate names are not allowed.")
-        if not is_list_like(names, allow_sets=False):
+        if not (
+            is_list_like(names, allow_sets=False) or isinstance(names, abc.KeysView)
+        ):
             raise ValueError("Names should be an ordered collection.")
 
 

pandas/tests/io/parser/test_common.py

@@ -2212,3 +2212,15 @@ def test_read_table_delim_whitespace_non_default_sep(all_parsers):
     )
     with pytest.raises(ValueError, match=msg):
         parser.read_table(f, delim_whitespace=True, sep=",")
+
+
+def test_dict_keys_as_names(all_parsers):
+    # GH: 36928
+    data = "1,2"
+
+    keys = {"a": int, "b": int}.keys()
+    parser = all_parsers
+
+    result = parser.read_csv(StringIO(data), names=keys)
+    expected = DataFrame({"a": [1], "b": [2]})
+    tm.assert_frame_equal(result, expected)