Persistence Forecast

Problem

The persistence (naive) forecast assumes every future value equals the last observed value. Return a list containing series[-1] repeated horizon times.

Return an empty list when the series is empty or horizon is not positive.

Hint

This is the benchmark any real forecast must beat.

Test cases

case 1

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

expected: [7,7,7]

case 2

in: [[2],2]

expected: [2,2]

case 3

in: [[],2]

expected: []

case 4

in: [[1,2],0]

expected: []

Starter codePython

def persistence_forecast(series, horizon):
    # Your code here
    pass

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