计算布尔列的百分比

Posted 2023-04-18

【中文标题】计算布尔列的百分比

【英文标题】：Calculate percentage on boolean column

【发布时间】：2018-02-03 00:55:01

【问题描述】：

假设我的数据具有以下结构：

Year      | Location | New_client 

2018      | Paris    | true
2018      | Paris    | true
2018      | Paris    | false
2018      | London   | true
2018      | Madrid   | true
2018      | Madrid   | false
2017      | Paris    | true

我正在尝试计算 New_client 的每一年和位置的真实值百分比，因此从结构示例中获取记录的示例是

2018     | Paris    | 66
2018     | London   | 100
2018     | Madrid   | 50
2017     | Paris    | 100

改编自 https://***.com/a/13484279/2802552 我当前的脚本是，但不同之处在于它使用 2 列（年份和位置）而不是 1 列

data = load...
grp = group inpt by Year; -- creates bags for each value in col1 (Year)
result = FOREACH grp 
    total = COUNT(data);
    t = FILTER data BY New_client == 'true'; --create a bag which contains only T values
    GENERATE FLATTEN(group) AS Year, total AS TOTAL_ROWS_IN_INPUT_TABLE, 100*(double)COUNT(t)/(double)total AS PERCENTAGE_TRUE_IN_INPUT_TABLE;
;

问题是这使用年份作为参考，而我需要它是年份和地区。

感谢您的帮助。

【参考方案1】：

您需要同时按Year 和Location 进行分组，这需要进行两次修改。首先，将Location 添加到group by 语句中。其次，将FLATTEN(group) AS Year 更改为FLATTEN(group) AS (Year, Location)，因为group 现在是一个包含两个字段的元组。

grp = group inpt by (Year, Location);
result = FOREACH grp 
    total = COUNT(inpt);
    t = FILTER inpt BY New_client == 'true';
    GENERATE 
        FLATTEN(group) AS (Year, Location), 
        total AS TOTAL_ROWS_IN_INPUT_TABLE, 
        100*(double)COUNT(t)/(double)total AS PERCENTAGE_TRUE_IN_INPUT_TABLE;
;

【参考方案2】：

测试了这段代码，看起来对我有用：

A = LOAD ...
B = GROUP A BY (year, location);
C = FOREACH B  
    TRUE_CNT = FILTER A BY (chararray)new_client == 'true';
    GENERATE group.year, group.location, (int)((float)COUNT(TRUE_CNT) / COUNT(A) * 100);


DUMP C;
(2017,Paris,100)
(2018,Paris,66)
(2018,London,100)
(2018,Madrid,50)