A bag of random elements to pick from. Usage: when you want to guarantee that a random event will occur an exact number of times, but want a random ordering. Good for RPG A.I., as it will prevent the AI from picking the same move too many times, but still have a skewed random pick.

RandomBag.py

import random

# A bag of random elements to pick from.
# Usage: when you want to guarantee that a random
# event will occur, but want a random ordering.
class RandomBag:

    # Build a bag. Fill it with counts using tuples
    # [('attack', 3), ('flee', 1), ...]
    def __init__(self, element_count_tuples=[]):
        self.bag = []
        for element, count in element_count_tuples:
            self.add(element, count)

    # Add some number of elements to the bag
    def add(self, element, amount=1):
        self.bag += [element] * amount
    
    # Pick a single element out of the bag
    def pick(self, remove_after_pick=True):
        if self.is_empty():
            return None
        pick = random.sample(self.bag, 1)[0]
        if remove_after_pick:
            self.bag.remove(pick)
        return pick
    
    # Is the bag empty (bool)
    def is_empty(self):
        return len(self.bag) == 0