updating df.query and df.eval docstrings. resolves #16283 #58749
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pandas/core/frame.py
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| You can refer to column names that are not valid Python variable names | ||
| by surrounding them in backticks. Thus, column names containing spaces | ||
| or punctuations (besides underscores) or starting with digits must be | ||
| surrounded by backticks. (For example, a column named "Area (cm^2)" would | ||
| be referenced as ```Area (cm^2)```). Column names which are Python keywords | ||
| (like "list", "for", "import", etc) cannot be used. | ||
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| For example, if one of your columns is called ``a a`` and you want | ||
| to sum it with ``b``, your query should be ```a a` + b``. |
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Can you demonstrate this in the Example section instead?
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I have added one example in the Example section. Note that above wording is coming from query function.
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I would remove all this explanation now that it's explained in the examples section
pandas/core/frame.py
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| 2 3 6 9 | ||
| 3 4 4 8 | ||
| 4 5 2 7 | ||
| A B C C C |
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These headers don't look correct anymore
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I double checked and it looks correct
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If you look at the examples here you can see 5 column labels for 4 columns: https://pandas.pydata.org/preview/pandas-dev/pandas/58749/docs/reference/api/pandas.DataFrame.eval.html
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Initial example dataframe contains 3 columns: A, B and C C. The eval method will add a fourth column named C in the resulting dataframe for this example.
Repr of the dataframe does not make the separation of columns obvious when columns contains spaces. It is like there is 3 columns C when you actually have C C and C.
To make the example cristal clear I may change C C by C&C and update the examples to add columns with names differents than C.
Do you want me to update also query examples as C C is actually coming from there ??
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To make the example cristal clear I may change C C by C&C and update the examples to add columns with names differents than C.
Ah yes that would be great. Sorry I didn't backtrack to see the context of the original columns
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shall I update query as well ?
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/preview |
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Website preview of this PR available at: https://pandas.pydata.org/preview/pandas-dev/pandas/58749/ |
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Thanks @mutricyl |
doc/source/whatsnew/vX.X.X.rstfile if fixing a bug or adding a new feature.This is a docstring improvement suggested in #16283 issue discussion.
df.evalanddf.queryare updated for consistency and adding exemples with@usage for local variables