How do I decompose a number into powers of 2?

Question

I\'m trying to create a function that receives a number as an argument and performs actions on that number to find out its closest powers of 2 that will then add up to that

Answer 1

The best and fastest way to do this is, of course, with binary numbers, but here's a way with a generator:

def powers_finder(num):
    d = []
    while sum(d) < num:
        p = powers_of_2()
        a=b=1
        while sum(d)+a<=num:
            b=a
            a = next(p)
        d.append(b)
    d.reverse()
    return d

def powers_of_2():
    n=1
    while 1:
        yield n
        n*=2

---

>>> print(powers_finder(5))
[1, 4]
>>> print(powers_finder(8))
[8]
>>> print(powers_finder(9))
[1, 8]
>>> print(powers_finder(14))
[2, 4, 8]