import random


def rand_sampling(ratio, stop, start=1) :
    """
    random sampling from close interval [start, stop]

    Args :
        ratio (float): percentage of sampling
        stop (int): upper bound of sampling interval
        start (int): lower bound of sampling interval
    
    Returns :
        A random sampling list
    """
    assert 0 <= ratio and ratio <= 100, 'The ratio must be between 0 and 100.'
    assert stop >= start, 'Invalid interval'

    sample_pool = [i for i in range(start, stop + 1)]
    select_num = int(len(sample_pool) * ratio)
    return sorted(random.sample(sample_pool, select_num))