fix bug in dataframe.from_records with str index and empty iterable i…

…ssue pandas-dev#47285

doc/source/whatsnew/v1.5.0.rst

@@ -776,7 +776,7 @@ Conversion
 Strings
 ^^^^^^^
 - Bug in :meth:`str.startswith` and :meth:`str.endswith` when using other series as parameter _pat_. Now raises ``TypeError`` (:issue:`3485`)
--
+- Bug in :meth:`DataFrame.from_records` raises a ``KeyError`` if passed a string index and an empty iterable (:isue:`#47285`)
 
 Interval
 ^^^^^^^^

pandas/core/frame.py

@@ -2291,6 +2291,13 @@ def maybe_reorder(
             arr_columns = ensure_index(arr_columns)
             if columns is None:
                 columns = arr_columns
+
+                if index is not None:
+                    if isinstance(index, str) or not hasattr(index, "__iter__"):
+                        if index not in columns:
+                            result_index = [index]
+                            index = None
+
             else:
                 arrays, arr_columns, result_index = maybe_reorder(
                     arrays, arr_columns, columns, index

pandas/tests/io/formats/test_info.py

@@ -491,3 +491,10 @@ def test_info_int_columns():
         """
     )
     assert result == expected
+
+def test_info_from_rec():
+    # GH47285
+    df = DataFrame.from_records([], index="foo")
+    print(df.info())
+    #buf = StringIO()
+    #df.info(buf=buf)