hierarchize.py

import math
from collections import defaultdict

def hierarchize(flatlist, func):
    output = defaultdict(list)
    for item in flatlist:
        output[func(item)].append(item)
    return output.values()
                
def evens(n):
    if n % 2 == 0: 
        return 1
    else:
        return 0
        
def primes(n):
    if n < 2: return 1
    if n == 2: return 0
    if n % 2 == 0: return 1    
    for i in xrange(3, int(math.sqrt(n)+1), 2):
        if n % i == 0: return 1
    return 0
        
print hierarchize([1,2,3,4,5,6,7,8,9,10,11,12,13,14,15], evens)
print hierarchize([1,2,3,4,5,6,7,8,9,10,11,12,13,14,15], primes)

# OUTPUT:
# [[1, 3, 5, 7, 9, 11, 13, 15], [2, 4, 6, 8, 10, 12, 14]]
# [[2, 3, 5, 7, 11, 13], [1, 4, 6, 8, 9, 10, 12, 14, 15]]