Random k unique numbers

random_k.py

import random


def random_k(start, end, k):
    seq = list(range(start, end))
    if len(seq) < k:
        raise ValueError('k too large.')
    n = len(seq)

    for i in range(0, min(k + 1, n - 1)):
        j = random.randint(i, n - 1)
        if i != j:
            seq[i], seq[j] = seq[j], seq[i]

    return seq[:k]