Python: map(), filter(), reduce() functions

Python: map(), filter(), reduce() functions

# map(), filter(), reduce() apply a function to every element in what you pass in
def add(a):
    return a + 10
arr = [1,2,3]
print(map(add, arr))  # returns 11, 12, 13

def gt_two(a):
    return a > 2
print(filter(gt_two, arr))  # returns [3]

from functools import reduce
def multiply(a, b):
    return a * b
print(reduce(multiply, arr))  # returns 6 - multiply every element in arr
print(reduce(multiply, arr, 2)) # return 12 - with an initial value