In [10]:
def num_digits(n):
    #return len(str(n))
    if n == 0:
        return 1
    count = 0
    while n != 0:
        n = n//10
        count += 1
    return count
In [11]:
num_digits(0)
Out[11]:
1
In [22]:
def extract_digits(n):
    #return len(str(n))
    if n == 0:
        return [0]
    result = []
    while n != 0:
        d = n%10
        n = n//10
        result = [d] + result
        #result.insert(0,d)
    return result
In [23]:
extract_digits(79824)
Out[23]:
[7, 9, 8, 2, 4]