I have a DataFrame:-
col count
0 B 1
1 B 2
2 A 1
3 A 2
4 A 3
5 C 1
6 C 2
7 C 3
8 C 4
wan to create new variable named Flag according to last occurrence of B , A in col variable. reference df:-
col count Flag
0 B 1 0
1 B 2 1
2 A 1 0
3 A 2 0
4 A 3 1
5 C 1 0
6 C 2 0
7 C 3 0
8 C 4 1
TIA
Use Series.duplicated with numpy.where:
df['Flag'] = np.where(df['col'].duplicated(keep='last'), 0, 1)
Or Series.view with invert mask by ~:
df['Flag'] = (~df['col'].duplicated(keep='last')).view('i1')
print (df)
col count Flag
0 B 1 0
1 B 2 1
2 A 1 0
3 A 2 0
4 A 3 1
5 C 1 0
6 C 2 0
7 C 3 0
8 C 4 1