jorisvandenbossche opened a new issue, #46179: URL: https://github.com/apache/arrow/issues/46179
### Describe the bug, including details regarding any error messages, version, and platform. The pandas -> arrow conversion adds a `__inex_level_i__` column if the dataframe has an unnamed it wants to preserve (i.e. if it is not just a pandas RangeIndex). But if your dataframe already has such a column, you end up with a duplicate field: ``` In [40]: df = pd.DataFrame({"col": [1, 2, 3], "__index_level_0__": [1, 2, 3]}, index=[2, 3, 4]) In [41]: df Out[41]: col __index_level_0__ 2 1 1 3 2 2 4 3 3 In [42]: pa.table(df) Out[42]: pyarrow.Table col: int64 __index_level_0__: int64 __index_level_0__: int64 ---- col: [[1,2,3]] __index_level_0__: [[1,2,3]] __index_level_0__: [[2,3,4]] ``` We could have it bump the integer number in the generated column? (although we would have to check how that works in the full roundtrip then) ### Component(s) Python -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: issues-unsubscr...@arrow.apache.org.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org