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;

预期产量：

 a
 b
 c

在Pig中声明逗号分隔的字符串常量的任何输入。

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

-使用（双引号）甚至使用转义字符（characters）声明常量导致出现以下WARN消息

-- 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-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 ）在ACTIVE_VALUES上使用函数获取字符包，可以对其进行FLATTEN处理以创建多个记录。可以将这些数据与测试文件中的数据进行内部联接，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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