Randomly chunk up an iterable, useful for sampling efficiently

strapper.py

import random

def chunks(whole, n_chunks):
    '''Randomly chunk up an iterable'''
    # Make sure that it makes sense to chunk up the object                                                            
    if n_chunks > len(whole) or n_chunks <= 0:
        yield whole
        return

    # Copy the iterable (we'll delete it later anyway) and shuffle it                                                 
    whole = whole.copy()
    random.shuffle(whole)

    # Calculate the chunk sizes                                                                                       
    whole_size = len(whole)
    chunk_size = int(whole_size / n_chunks)
    remainder = whole_size % n_chunks

    # Chunk it up                                                                                                     
    for start in range(0, n_chunks):
        end = (start + 1)*chunk_size
        # Add the remainder for the final chunk                                                                       
        if start == n_chunks - 1:
            end += remainder
        yield whole[start*chunk_size: end]
    # Clean up                                                                                                        
    del whole