generate_random_str.py

import collections
import random
import string
from typing import List

numbers: str = string.digits
lowers: str = string.ascii_lowercase
uppers: str = string.ascii_uppercase


def gen(length: int) -> str:
    # b is bulkhead choice
    b = sorted(random.sample(range(length - 1), k=2))
    x1 = b[0] + 1
    x2 = b[1] - b[0]
    x3 = length - b[1] - 1
    n = random.choices(numbers, k=x1)
    l = random.choices(lowers, k=x2)
    u = random.choices(uppers, k=x3)
    seq = n + l + u
    return ''.join(random.sample(seq, k=len(seq)))

def count_distribution(gens):
    elems = [x for y in gens for x in y]
    counts = collections.Counter(elems)
    return [counts, {x:sum([counts[y] for y in eval(x)]) for x in ["numbers", "lowers", "uppers"]}]

if __name__ == "__main__":
    random.seed(1)
    print(count_distribution((gen(15) for _ in range(100_000))))