I have a 200,000 x 500 dataframe loaded into Pandas. Is there a function that can automatically tell me which columns are missing data? Or do I have to iterate over each column and check element by element?
Once I've found a missing element, how do I define a custom function (based on both the column name and some other data in the same row) to do automatic replacements. I see the fillna() method, but I don't think it takes a (lambda) function as an input.
Thanks!