DOC: Outdated example of DataFrame.mean

[rafael-patronilo]

Pandas version checks

• I have checked that the issue still exists on the latest versions of the docs on main here

Location of the documentation

https://pandas.pydata.org/docs/dev/reference/api/pandas.DataFrame.mean.html#pandas.DataFrame.mean

Documentation problem

The second example specifies no axis and shows the mean for each column. According to the documentation above, the behavior when the axis is not specified should be to aggregate the mean over both axis since version 2.0.0

I didn't check if the same mistake is present in other aggregation functions.

Suggested fix for documentation

Replace df.mean() with df.mean(axis=0) on the example.

[rafael-patronilo]

I think I misunderstood the docs; I think it is only if you specify df.mean(axis=None) that it aggregates over both axes.