sum - PIG : sum and division, 创建对象

Question

我正在编写一个 Pig 程序，该程序加载一个用制表符分隔整个文件的文件

例如:名称 TAB 年份 TAB 计数 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;

问题在于我尝试创建的组操作对象。 我想要对所有匹配计数求和，对所有数量计数求和，然后将匹配计数除以数量计数。

我在算术运算/对象创建中做错了什么？ 我收到的错误是第 7 行，第 11 列> Pig 脚本无法验证:org.apache.pig.impl.ologicalLayer.FrontendException:错误 1031:不兼容的架构:左侧为“类型:NULL，年份: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

输入.txt

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

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;

输出:

(A,6.0)
(B,14.0)