Multiple Nested loops:: Fast nested loop function to use with your data processing (with variable list input).

fast-nested-loop.py

'''Intro
If you have "Multiple Nested loops" to operate on a list with O(n^k) complexity,
Save time complex on itermediate list operations by utilizing python map-reduce!
'''

import numpy as np
from itertools import product
import time

'''Proposed
Nested loop maper
'''
def quick_nested_loop(fn, *args):
    try:
        maper = map(lambda *x: fn(*x), product(*args[0]))
    except Exception as e:
        print(e) # Do something
        maper = None
    return maper

'''
Example Function to apply any operations on multiple (n-) lists
'''
def export(args):
    one, two, three = args
    return str(one)+str(two)+str(three)


#---------------------------------------
# TESTS


if __name__ == "__main__":
    ls1 = np.arange(100).tolist()
    ls2 = np.arange(100).tolist()
    ls3 = np.arange(1000).tolist()

    '''
    Using function with 3 nested for loop
    '''
    strt_time = time.time()
    result_list=[]
    for i in ls1:
        for j in ls2:
            for k in ls3:
                result_list.append(export([i,j,k]))
    print("Finished time - O(n^3) loop: ", time.time() - strt_time)
    # Finished time - O(n^3) loop:  11.05464506149292


    '''
    Function with map-based nested loop
    '''
    strt_time = time.time()
    maper = quick_nested_loop(export, [ls1, ls2, ls3])
    result_list = map(list, [maper])
    print("Finished time - quick nesting loop: ", time.time() - strt_time)
    # Finished time - quick nesting loop:  0.4097409248352051