How to flatten a pandas dataframe with some columns as json?

Question

I have a dataframe df that loads data from a database. Most of the columns are json strings while some are even list of jsons. For example:

id           


        

Answer 1

create a custom function to flatten columnB then use pd.concat

def flatten(js):
    return pd.DataFrame(js).set_index('pos').squeeze()

pd.concat([df.drop(['columnA', 'columnB'], axis=1),
           df.columnA.apply(pd.Series),
           df.columnB.apply(flatten)], axis=1)