Utils.py 文件源码

def sample_dict(dictionary, sample_size):
    """Return a randomly sampled frequency dict"""
    new_dict = dict()
    num_to_sample = sample_size
    num_to_process = sum(itervalues(dictionary))
    for (k, v) in iteritems(dictionary):
        for i in range(v):
            if random.random() < num_to_sample / num_to_process:
                new_dict[k] = new_dict.get(k, 0) + 1
                num_to_sample -= 1
            num_to_process -= 1
            if num_to_sample == 0:
                break
        else:
            continue
        break
    if num_to_sample > 0:
        raise ValueError(u'Not enough elements in dictionary')
    return new_dict