猪编程使用分组计数（*） [英] pig programming to use split on group by having count(*)

问题描述

输入文件是：

  2，玉米片，普通磨粉机，12美元b 3美元，玉米片，混合坚果，邮政，14 
 4，巧克力糖浆，普通，Hersheys，5 
 5，巧克力糖浆，无高果糖，贺喜饼，8 
 6，巧克力糖浆，普通，Ghirardeli，6美元b $ b 7，巧克力糖浆，草莓味，Ghirardeli，7 
 
 filter3 =使用PigStorage（'\t'）作为LOAD'location_of_file'（item_sl：int，item：chararray，type：chararray ，制造商：chararray，价格：诠释）; 
 
 SPLIT filter3 INTO filter4 IF（FOREACH（filter3 GROUP BY item）GENERATE group，COUNT（item< 3）），filter6_pass OTHERWISE; 
  

这就好像有一个带有一个group by by项的count（*）< 3

所需的输出是：

  4，巧克力糖浆，常规，Hersheys，5 
 5，巧克力糖浆，高果糖，赫尔希什，8 
 6，巧克力糖浆，普通，Ghirardeli，6 
 7，巧克力糖浆，草莓味，Ghirardeli，7 
  

解决方案

按项目分组，然后使用过滤器在计数中使用PigStorage（'\ t'）作为（item_sl：int，item： chararray，类型：chararray，制造商：chararray，价格：int）;
B = GROUP A BY item;
C = FOREACH B GENERATE组，COUNT（A.item）AS总计;
D = FILTER C BY总计> 3;
E =加入一个BY项目，D BY $ 0;
F = FOREACH E GENERATE $ 0 .. $ 4;
DUMP F;

Input file is:

2, cornflakes, Regular,General Mills, 12
3, cornflakes, Mixed Nuts, Post, 14
4, chocolate syrup, Regular, Hersheys, 5
5, chocolate syrup, No High Fructose, Hersheys, 8
6, chocolate syrup, Regular, Ghirardeli, 6
7, chocolate syrup, Strawberry Flavor, Ghirardeli, 7

filter3 = LOAD 'location_of_file' using PigStorage('\t') as (item_sl : int, item : chararray, type: chararray, manufacturer: chararray, price : int);

SPLIT filter3 INTO filter4 IF (FOREACH (filter3 GROUP BY item) GENERATE group, COUNT(item < 3)), filter6_pass OTHERWISE;

It is like having a SQL with a group by on item having count(*) < 3

The desired output is:

4, chocolate syrup, Regular, Hersheys, 5
5, chocolate syrup, No High Fructose, Hersheys, 8
6, chocolate syrup, Regular, Ghirardeli, 6
7, chocolate syrup, Strawberry Flavor, Ghirardeli, 7

解决方案

Group by item, get the count and then use filter on the count

A = LOAD 'location_of_file' using PigStorage('\t') as (item_sl : int, item : chararray, type: chararray, manufacturer: chararray, price : int);
B = GROUP A BY item;
C = FOREACH B GENERATE group,COUNT(A.item) AS Total;
D = FILTER C BY Total > 3;
E = JOIN A BY item,D BY $0;
F = FOREACH E GENERATE $0..$4;
DUMP F;

这篇关于猪编程使用分组计数（*）的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！