BUG: `pprint_thing(..., quote_strings=True)` fails for strings with embedded single-quotes

[zpincus]

Pandas version checks

• I have checked that this issue has not already been reported.

• I have confirmed this bug exists on the latest version of pandas.

• I have confirmed this bug exists on the main branch of pandas.

Reproducible Example

from pandas.io.formats.printing import pprint_thing

print(pprint_thing("'510", quote_strings=True))

Issue Description

The code above produces the incorrect ''510' as output, instead of "'510" as python does, or even '\'510'.

In the current master the cause is clear enough:

    elif isinstance(thing, str) and quote_strings:
        result = f"'{as_escaped_string(thing)}'"

Either python's string repr could be used (assuming the rest of its behavior is fit for the purpose), or single-quotes could be explicitly backslash-escaped.

Expected Behavior

As above.

Installed Versions

As above, but is present in GitHub master as of right now.

[rhshadrach]

Thanks for the report. While this method is not public, the issue can manifest in e.g.

df = pd.DataFrame({"'a": [1, 1, 2], "b": [3, 4, 5], "c": 6}).set_index(["'a", "b"])
print(df.index.names)
# [''a', 'b']

PRs to fix are welcome!

[thedataninja1786]

take

[thedataninja1786]

This can be addressed by modifying __str__ in ..\core\indexes\frozen.py to include single quotes also def __str__(self) -> str: return pprint_thing(self, quote_strings=True, escape_chars=("\t", "\r", "\n","'")) and extending pprint_thing's to translate = {"\t": r"\t", "\n": r"\n", "\r": r"\r", "'":""} in ..\printing.py to remove them. I believe escaping single quotes does not work here since the output itself is wrapped in single quotes.