Question

我正在编写一个猪程序，它加载一个文件，用于分隔其entires和tabs

ex：name TAB year TAB count TAB ...

file = LOAD 'file.csv' USING PigStorage('\t') as (type: chararray, year: chararray,
match_count: float, volume_count: float);

-- Group by type
grouped = GROUP file BY type;

-- Flatten
by_type = FOREACH grouped GENERATE FLATTEN(group) AS (type, year, match_count, volume_count);

group_operat = FOREACH by_type GENERATE  
        SUM(match_count) AS sum_m,
        SUM(volume_count) AS sum_v,
       (float)sum_m/sm_v;

DUMP group_operat;

问题在于我正在尝试创建的组操作对象。 我想要将所有匹配计数相加，将所有体积计数相加并将匹配计数除以体积计数。

在算术运算/对象创建中我做错了什么？我收到的错误是第7行，第11列＆gt; pig脚本无法验证：org.apache.pig.impl.logicalLayer.FrontendException：错误1031：不兼容的架构：左边是“type：NULL，year：NULL，match_count：NULL，volume_count：NULL”，右边是“group：chararray “

谢谢。

Answer 1

尝试这样，这将返回类型和总和。

更新了工作代码

<强> input.txt中

A       2001     10      2
A       2002     20      3
B       2003     30      4
B       2004     40      1

<强> PigScript：

file = LOAD 'input.txt' USING PigStorage() AS (type: chararray, year: chararray,
match_count: float, volume_count: float);
grouped = GROUP file BY type;
group_operat = FOREACH grouped {
                                 sum_m = SUM(file.match_count);
                                 sum_v = SUM(file.volume_count);
                                 GENERATE group,(float)(sum_m/sum_v) as sum_mv;
                                }
DUMP group_operat;

<强>输出：

(A,6.0)
(B,14.0)

Answer 2

试试这个，

file = LOAD 'file.csv' USING PigStorage('\t') as (type: chararray, year: chararray,
match_count: float, volume_count: float);

grouped = GROUP file BY (type,year);

group_operat = FOREACH grouped GENERATE group,
        SUM(file.match_count) AS sum_m,
        SUM(file.volume_count) AS sum_v,
       (float)(SUM(file.match_count)/SUM(file.volume_count)) as sum_mv;

上面的脚本按类型和年份给出结果组，如果您只想按类别分组，则从分组中删除

grouped = GROUP file BY type;

group_operat = FOREACH grouped GENERATE group,file.year,
        SUM(file.match_count) AS sum_m,
        SUM(file.volume_count) AS sum_v,
       (float)(SUM(file.match_count)/SUM(file.volume_count)) as sum_mv;

PIG：求和除法，创建一个对象

2 个答案: