pandas - Select last observed value from a column in a data frame

Question

I have a df like this:

ColumnA             ColumnB
TCK01/TCK02/TCK03   date1
TCK04               date2
TCK05/TCK06         date3

I want to sum the two columns but only keeping the last observed value (or if there is only one keep it) in the ColumnA and adding a "-" between the values, to get something like this:

ColumnA             ColumnB     Column AB
TCK01/TCK02/TCK03   date1       TCK03-date1
TCK04               date2       TCK04-date2
TCK05/TCK06         date3       TCK06-date3

question from:https://stackoverflow.com/questions/65889759/select-last-observed-value-from-a-column-in-a-data-frame

Answer 1

Regex based Solution:

df['Column AB'] = df['ColumnA'].str.extract(r'(T[^/]+)$')[0] + '-' + df['ColumnB']

---

df:

    ColumnA             ColumnB Column AB
0   TCK01/TCK02/TCK03   date1   TCK03-date1
1   TCK04               date2   TCK04-date2
2   TCK05/TCK06         date3   TCK06-date3

For regex explanation: https://regex101.com/r/TwslQu/1