hadoop - 如何从 Pig 中的关系生成自定义模式？

Question

我有一个描述各种文章中单词的 tf-idf 值的模式。它的描述如下:

tfidf_relation: {word: chararray,id: bytearray,tfidf: double}

这是此类数据的示例:

(cat,article_one,0.13515503603605478)
(cat,article_two,0.4054651081081644)
(dog,article_one,0.3662040962227032)
(apple,article_three,0.3662040962227032)
(orange,article_three,0.3662040962227032)
(parrot,article_one,0.13515503603605478)
(parrot,article_three,0.13515503603605478)

我想以一种形式获得输出:猫article_one 0.13515503603605478，article_two 0.4054651081081644等等。问题是，我如何从这个包含单词字段和 id 和 tfidf 字段的元组的关系中建立关系？像这样:

X = FOREACH tfidf_relation GENERATE word, (id, tfidf);

没用。正确的语法是什么？

Answer 1

试试这个:

    t = LOAD 'input/file' USING PigStorage(',') as (word: chararray,id: bytearray,tfidf: double);
    u = group t by word;
    dump u;

输出将是

    (cat,{(cat,article_two,0.4054651081081644),(cat,article_one,0.13515503603605478)})
    (dog,{(dog,article_one,0.3662040962227032)})
    (apple,{(apple,article_three,0.3662040962227032)})
    (orange,{(orange,article_three,0.366204096222703)})
    (parrot,{(parrot,article_three,0.13515503603605478),
    (parrot,article_one,0.13515503603605478)})

希望这就是您要找的。