BUG: escape single quotes in index names when printing (#60251)

doc/source/whatsnew/v3.0.0.rst

@@ -667,7 +667,7 @@ Indexing
 ^^^^^^^^
 - Bug in :meth:`DataFrame.__getitem__` returning modified columns when called with ``slice`` in Python 3.12 (:issue:`57500`)
 - Bug in :meth:`DataFrame.from_records` throwing a ``ValueError`` when passed an empty list in ``index`` (:issue:`58594`)
--
+- Bug in printing :attr:`Index.names` and :attr:`MultiIndex.levels` would not escape single quotes (:issue:`60190`)
 
 Missing
 ^^^^^^^

pandas/core/indexes/frozen.py

@@ -110,7 +110,9 @@ def _disabled(self, *args, **kwargs) -> NoReturn:
         raise TypeError(f"'{type(self).__name__}' does not support mutable operations.")
 
     def __str__(self) -> str:
-        return pprint_thing(self, quote_strings=True, escape_chars=("\t", "\r", "\n"))
+        return pprint_thing(
+            self, quote_strings=True, escape_chars=("\t", "\r", "\n", "'")
+        )
 
     def __repr__(self) -> str:
         return f"{type(self).__name__}({self!s})"

pandas/io/formats/printing.py

@@ -203,7 +203,7 @@ def pprint_thing(
     def as_escaped_string(
         thing: Any, escape_chars: EscapeChars | None = escape_chars
     ) -> str:
-        translate = {"\t": r"\t", "\n": r"\n", "\r": r"\r"}
+        translate = {"\t": r"\t", "\n": r"\n", "\r": r"\r", "'": r"\'"}
         if isinstance(escape_chars, Mapping):
             if default_escapes:
                 translate.update(escape_chars)

pandas/tests/io/formats/test_printing.py

@@ -3,11 +3,33 @@
 from collections.abc import Mapping
 import string
 
+import pytest
+
 import pandas._config.config as cf
 
+import pandas as pd
+
 from pandas.io.formats import printing
 
 
+@pytest.mark.parametrize(
+    "input_names, expected_names",
+    [
+        (["'a b"], "['\\'a b']"),  # Escape leading quote
+        (["test's b"], "['test\\'s b']"),  # Escape apostrophe
+        (["'test' b"], "['\\'test\\' b']"),  # Escape surrounding quotes
+        (["test b'"], "['test b\\'']"),  # Escape single quote
+        (["test\n' b"], "['test\\n\\' b']"),  # Escape quotes, preserve newline
+    ],
+)
+def test_formatted_index_names(input_names, expected_names):
+    # GH#60190
+    df = pd.DataFrame({name: [1, 2, 3] for name in input_names}).set_index(input_names)
+    formatted_names = str(df.index.names)
+
+    assert formatted_names == expected_names
+
+
 def test_adjoin():
     data = [["a", "b", "c"], ["dd", "ee", "ff"], ["ggg", "hhh", "iii"]]
     expected = "a  dd  ggg\nb  ee  hhh\nc  ff  iii"