Give every day a band number: 0 below 1200, 1 from 1200 to below 1800, 2 from 1800 upwards. Use np.digitize with the edges [1200, 1800] and store the band numbers in result.
import numpy as np sales = np.array([1200, 1350, 980, 1500, 1720, 2100, 1900, 1250, 1400, 1010, 1580, 1800, 2250, 2050]) costs = np.array([800, 850, 700, 900, 1000, 1200, 1100, 820, 870, 720, 950, 1050, 1300, 1150])
Store your final answer in a variable named result.
Each hint gives a little more help. Try on your own first.
Run your code to see the output here.