BUG: GH36928 Allow dict_keys to be used as column names by read_csv

doc/source/whatsnew/v1.1.4.rst

@@ -14,7 +14,7 @@ including other versions of pandas.
 
 Fixed regressions
 ~~~~~~~~~~~~~~~~~
--
+- `dict_keys` not being accepted as valid column names by `pandas.io.parsers._validate_names`
 
 .. ---------------------------------------------------------------------------
 

pandas/_libs/lib.pyx

@@ -1019,8 +1019,6 @@ cdef inline bint c_is_list_like(object obj, bint allow_sets) except -1:
         and not (util.is_array(obj) and obj.ndim == 0)
         # exclude sets if allow_sets is False
         and not (allow_sets is False and isinstance(obj, abc.Set))
-        # allow dict_keys objects
-        or isinstance(obj, abc.KeysView)
     )
 
 

pandas/io/parsers.py

@@ -420,7 +420,9 @@ 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) and not isinstance(
+            names, abc.KeysView
+        ):
             raise ValueError("Names should be an ordered collection.")
 
 

pandas/tests/io/parser/test_common.py

@@ -2224,9 +2224,12 @@ def test_read_table_delim_whitespace_non_default_sep(all_parsers):
 
 
 def test_dict_keys_as_names(all_parsers):
-    data = "a,b\n1,2"
+    # GH: 36928
+    data = "1,2"
 
     keys = {"a": int, "b": int}.keys()
     parser = all_parsers
 
-    parser.read_csv(StringIO(data), names=keys)
+    result = parser.read_csv(StringIO(data), names=keys)
+    expected = DataFrame({"a": [1], "b": [2]})
+    tm.assert_frame_equal(result, expected)