numbers = [
              [34, 63, 88, 71, 29],
              [90, 78, 51, 27, 45],
              [63, 37, 85, 46, 22],
              [51, 22, 34, 11, 18]
           ]

averages = list(map(lambda x: sum(x) / len(x), numbers))
print(averages)

[57.0, 58.2, 50.6, 27.2]

cities = ["New York City", "Los Angeles", "Chicago", "Mountain View", "Denver", "Boston"]

short_cities = list(filter(lambda x: len(x) < 10, cities))
print(short_cities)

['Chicago', 'Denver', 'Boston']