Append All Columns From One Row Into Another Row

I am trying to append every column from one row into another row, I want to do this for every row, but some row will not have any values, take a look at my code it will be more cle

Solution 1:

Use DataFrame.join with remove column next_calendarday_nextday:

df = df.set_index('date')
df = (df.join(df, on='next_calendarday', rsuffix='_nextday')
        .drop('next_calendarday_nextday', axis=1))