BUG: Fix dir(interval_index)

doc/source/whatsnew/v0.25.1.rst

@@ -78,7 +78,7 @@ Strings
 
 Interval
 ^^^^^^^^
-
+- Bug in :class:`IntervalIndex` where `dir(obj)` would raise ``ValueError`` (:issue:`27571`)
 -
 -
 -

pandas/core/strings.py

@@ -27,6 +27,7 @@
 from pandas.core.algorithms import take_1d
 from pandas.core.base import NoNewAttributesMixin
 import pandas.core.common as com
+from pandas.core.construction import extract_array
 
 _cpython_optimized_encoders = (
     "utf-8",
@@ -1950,11 +1951,14 @@ def _validate(data):
         # see _libs/lib.pyx for list of inferred types
         allowed_types = ["string", "empty", "bytes", "mixed", "mixed-integer"]
 
-        values = getattr(data, "values", data)  # Series / Index
+        values = extract_array(data)  # unpack Series / Index
         values = getattr(values, "categories", values)  # categorical / normal
 
-        # missing values obfuscate type inference -> skip
-        inferred_dtype = lib.infer_dtype(values, skipna=True)
+        try:
+            # GH#27571 make sure this doesn't raise too early
+            inferred_dtype = lib.infer_dtype(values, skipna=True)
+        except (ValueError, TypeError):
+            inferred_dtype = None
 
         if inferred_dtype not in allowed_types:
             raise AttributeError("Can only use .str accessor with string values!")

pandas/tests/indexes/interval/test_interval.py

@@ -1095,3 +1095,10 @@ def test_is_all_dates(self):
         )
         year_2017_index = pd.IntervalIndex([year_2017])
         assert not year_2017_index.is_all_dates
+
+
+def test_dir():
+    # GH#27571 dir(interval_index) should not raise
+    index = IntervalIndex.from_arrays([0, 1], [1, 2])
+    result = dir(index)
+    assert "str" not in result