locate the numeric position of a non numeric index value

Question

Consider the series s below:

s = pd.Series(np.arange(18, 0, -3), list(\'ABCDEF\'))
s

A    18
B    15
C    12
D     9
E     6
F     3
dtype: int         


        

Answer 1

m = s.index == 'D'
idx = m.argmax() if m.any() else None