How to drop column according to NAN percentage for dataframe?

Question

For certain columns of df, if 80% of the column is NAN.

What\'s the simplest code to drop such columns?

Answer 1

As suggested in comments, if you use sum() on a boolean test, you can get the number of occurences.

Code:

def get_nan_cols(df, nan_percent=0.8):
    threshold = len(df.index) * nan_percent
    return [c for c in df.columns if sum(df[c].isnull()) >= threshold]  

Used as:

del df[get_nan_cols(df, 0.8)]