Question

以下是我拥有的数据和架构，以下是 - student_name，question_number，actual_result（任意 - 假/正确）

(b,q1,Correct)
(a,q1,false)
(b,q2,Correct)
(a,q2,false)
(b,q3,false)
(a,q3,Correct)
(b,q4,false)
(a,q4,false)
(b,q5,flase)
(a,q5,false)

我想要的是获得每个学生的计数，即a / b总数他/她做出的正确和错误的答案。

Answer 1

对于共享的用例，下面的猪脚本就足够了。

猪脚本：

student_data = LOAD 'student_data.csv' USING PigStorage(',') AS (student_name:chararray, question_number:chararray, actual_result:chararray);
student_data_grp = GROUP student_data BY student_name;
student_correct_answer_data = FOREACH student_data_grp {
    answers = student_data.actual_result;
    correct_answers = FILTER answers BY actual_result=='Correct';
    incorrect_answers = FILTER answers BY actual_result=='false';
    GENERATE group AS student_name, COUNT(correct_answers) AS correct_ans_count, COUNT(incorrect_answers) AS incorrect_ans_count ;
};

输入：student_data.csv：

b,q1,Correct
a,q1,false
b,q2,Correct
a,q2,false
b,q3,false
a,q3,Correct
b,q4,false
a,q4,false
b,q5,false
a,q5,false

输出：DUMP kpi：

-- schema : (student_name, correct_ans_count, incorrect_ans_count)
(a,1,4)
(b,2,3)

参考：有关嵌套FOR EACH

的详细信息

Answer 2

使用此：

data = LOAD '/abc.txt' USING PigStorage(',') AS (name:chararray, number:chararray,result:chararray);
B = GROUP data by (name,result);
C = foreach B generate FLATTEN(group) as (name,result), COUNT(data) as count;

并且答案如下：

(a,false,4)
(a,Correct,1)
(b,false,3)
(b,Correct,2)

希望这是您正在寻找的输出

通过对数据包进行迭代计算，但对于与该字段关联的每个值，条件应该是不同的计数

2 个答案: