warn about missing coiumns

[wankoelias]

In pandera there is the strict option to raise an schema_error if not all columns in the dataframe are defined in the schema.

I would like to warn about this without raising an error. Ideally also with a flag e.g. undefined_cols_warning = True.

If this is too exotic I would love to have the ability to add such a warning through pandera extensions - right now I don't think this is possible

[cosmicBboy]

hi @wankoelias, good question: what do you think about something like strict="raise_warning"? The filter string is already an acceptable argument so I don't see way "raise_warning" shouldn't be supported.