ENH: give a useful error message when .query is used on a dataframe with duplicate column names

[Mo-Gul]

Feature Type

• Adding new functionality to pandas

• Changing existing functionality in pandas

• Removing existing functionality in pandas

Problem Description

The title says it all. Optimally .query would give the same error message as the alternative given in the MWE below.

Feature Description

see MWE below

Alternative Solutions

see MWE below

Additional Context

# %%
import pandas as pd

df = pd.DataFrame(
    {
        "A": range(1, 6),
        "B": range(10, 0, -2),
        "C": range(10, 5, -1),
    },
)

# %%
# rename columns with duplicate names
df.columns = ["A", "B", "A"]

# %%
# gives useful error message:
# ValueError: cannot reindex on an axis with duplicate labels
df[(df.A <= 4) & (df.B <= 8)]

# %%
# does not give useful error message:
# TypeError: dtype 'A    int64
# A    int64
# dtype: object' not understood
df.query("A <= 4 and B <= 8")