Determining the cumulative maximum of a column

Question

I am trying the following code

df = pd.DataFrame([[23, 52], [36, 49], [52, 61], [75, 82], [97, 12]], columns=[\'A\', \'B\'])
df[\'C\'] = np.where(df[\'A\'] &         


        

Answer 1

you need cummax:

df['C'] = df.A.cummax()