如何标记正负样本

[zscwind]

嗨，您好。请问正负样本是如何标记的呢？
    for key in user_map:
    sorted_user_bh = sorted(user_map[key], key=lambda x:x[1])
    for line, t in sorted_user_bh:
        items = line.split("\t")
        asin = items[1]
        j = 0
        while True:
            asin_neg_index = random.randint(0, len(item_list) - 1)
            asin_neg = item_list[asin_neg_index]
            if asin_neg == asin:
                continue 
            items[1] = asin_neg
            print>>fo, "0" + "\t" + "\t".join(items) + "\t" + meta_map[asin_neg]
            j += 1
            if j == 1:             #negative sampling frequency
                break
        if asin in meta_map:
            print>>fo, "1" + "\t" + line + "\t" + meta_map[asin]
        else:
            print>>fo, "1" + "\t" + line + "\t" + "default_cat"

看这段代码，负样本是随机生成的？

[zscwind]

@mouna99 可以详解一下样本的构造过程吗？