PIG如何计算别名中的行数 [英] PIG how to count a number of rows in alias

问题描述

  logs = LOAD'log'这是我在做这样的事情来计算PIG别名中的行数。 
 logs_w_one = foreach日志生成1为一个; 
 logs_group =组logs_w_one all; 
 logs_count = foreach logs_group生成SUM（logs_w_one.one）; 
转储logs_count; 
  

这似乎太低效了。如果有更好的方法，请赐教！

解决方案

COUNT是猪的一部分查看手册

  LOGS = LOAD'log' ; 
 LOGS_GROUP =组日志全部; 
 LOG_COUNT = FOREACH LOGS_GROUP GENERATE COUNT（LOGS）; 
  

I did something like this to count the number of rows in an alias in PIG:

logs = LOAD 'log'
logs_w_one = foreach logs generate 1 as one;
logs_group = group logs_w_one all;
logs_count = foreach logs_group generate SUM(logs_w_one.one);
dump logs_count;

This seems to be too inefficient. Please enlighten me if there is a better way!

解决方案

COUNT is part of pig see the manual

LOGS= LOAD 'log';
LOGS_GROUP= GROUP LOGS ALL;
LOG_COUNT = FOREACH LOGS_GROUP GENERATE COUNT(LOGS);

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