k #sample_num
            data #待抽样数据，array
            reservoir_array[k] #抽样数组 
            init reservoir_array in k #计算抽样数组
            for i = k + 1 ; do
                sample_num = randint(0 , i)
                if sample_num < k: #如果随机数落在 [1,k]区域内，则data[sample_num],替换成data[i]
                    reservoir_array[sample_num] = data[i]
            done 

 
        sample_rate #抽样概率
        sample_array #抽样存放数组
        sample_probality = random(0,1)
        for i = 0 ; i < len(data) ;do
            if sample_probality < sample_rate:
                sample_array.append(data[i])
        done