how do I calculate a rolling idxmax

Question

consider the pd.Series s

import pandas as pd
import numpy as np

np.random.seed([3,1415])
s = pd.Series(np.random.randint(0, 10, 10         


        

Answer 1

I used a generator

def idxmax(s, w):
    i = 0
    while i + w <= len(s):
        yield(s.iloc[i:i+w].idxmax())
        i += 1

pd.Series(idxmax(s, 3), s.index[2:])

c    c
d    c
e    e
f    e
g    e
h    f
i    i
j    i
dtype: object