声明一个逗号分隔的字符串常量 [英] Declare a comma seperated string constant

问题描述

目标:声明一个逗号分隔的字符串常量

    test.csv
    =========
    a
    b
    c
    d
    e
    f

猪脚本:

  %declare ACTIVE_VALUES 'a', 'b','c' ; 

  -- Declaring constant like this using "" (double quotes) or even using escape characters (\) is resulting in a WARN message as below 
  -- WARN  org.apache.pig.tools.parameters.PreprocessorContext - Warning : Multiple values found for ACTIVE_VALUES

  A = LOAD 'test.csv' using PigStorage(',') AS (value:chararray);
  B = FILTER A BY value in ($ACTIVE_VALUES);
  dump B;

预期输出:

 a
 b
 c

在 Pig 中声明逗号分隔字符串常量的任何输入.

Any inputs on declaring a comma separated string constant in Pig.

-- 像这样使用"(双引号)甚至使用转义字符(\)声明常量会导致如下警告消息

-- Declaring constant like this using "" (double quotes) or even using escape characters (\) is resulting in a WARN message as below

-- 警告 org.apache.pig.tools.parameters.PreprocessorContext - 警告:为 ACTIVE_VALUES 找到多个值

-- WARN org.apache.pig.tools.parameters.PreprocessorContext - Warning : Multiple values found for ACTIVE_VALUES

推荐答案

您可以使用单个逗号分隔的字符串 ('a,b,c') 并使用 STRSPLIT (https://pig.apache.org/docs/r0.9.1/func.html#strsplit) ACTIVE_VALUES 函数获取字符包，可以将其压平以创建多个记录.可以将这些数据与测试文件中的数据进行 INNER JOIN，以获得所需的结果.

You can use a single comma delimited string ('a,b,c') and use STRSPLIT (https://pig.apache.org/docs/r0.9.1/func.html#strsplit) function on ACTIVE_VALUES to get bag of characters, which can be FLATTEN'd to create multiple records. This data can be INNER JOIN'ed with data from test file to get the desired results.

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