pandas の full outer join
df = pd.DataFrame(np.random.randint(0,100,size=(3, 4)), columns=list('ABCD')) df['_index'] = 1 pd.merge(df[['_index', 'A']], df[['_index','B']], how='outer', on='_index') df.drop(columns=['_index'], inplace=True)
df = pd.DataFrame(np.random.randint(0,100,size=(3, 4)), columns=list('ABCD')) df['_index'] = 1 pd.merge(df[['_index', 'A']], df[['_index','B']], how='outer', on='_index') df.drop(columns=['_index'], inplace=True)