apache pig，按 id 分组的值的排列

Question

使用 Apache Pig，我需要一个字段的所有排列，按 id 字段（在本例中为“标题”）分组。输入数据如下所示：

架构是 {chararray, chararray}

(title1, name1)
(title1, name2)
(title1, name3)
(title2, name4)
(title2, name5)
(title2, name6)

我需要 title1 名称关系和 title2 名称关系在一个列表中的所有排列。期望的输出是：

(name1, name2)
(name1, name3)
(name2, name3)
(name4, name5)
(name4, name6)
(name5, name6)

我找到了这个相关的答案How To Find All Possible Permutations From A Bag under apache pig，但我在扩展解决方案以限制每个标题字段的排列时遇到了困难。

Answer 1

在做了更多搜索之后，使用这两个帖子： How To Find All Possible Permutations From A Bag under apache pig , PIG: Get all tuples out of a grouped bag 引导我找到这个解决方案：

输入模式是 {chararray, chararray}

inpt = foreach input generate $0 as (id:chararray), $1 as (val);
grp = group inpt by (id);
id_grp = foreach grp generate group as id, inpt.val as value_bag;
result = foreach id_grp generate FLATTEN(value_bag) as v1,FLATTEN(value_bag) as v2; 
result = filter result by v1 <= v2;
result = filter result by v1 != v2;