Seasonal Naive Forecast

Problem

The seasonal naive forecast predicts the next value with the observation from one full season ago: forecast = series[-season_length].

Return None if season_length is not positive or exceeds the series length.

Hint

Python's negative indexing does the work once you validate the inputs.

case 1

in: [[10,20,30,40,50,60],4]

expected: 30

case 2

in: [[1,2,3,4],1]

expected: 4

case 3

in: [[5,7,9],3]

expected: 5

case 4

in: [[1,2],5]

expected: null

Starter codePython

def seasonal_naive_forecast(series, season_length):
    # Your code here
    pass

4 test cases · run your code against them in the editor