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From "Santhosh Srinivasan" <...@yahoo-inc.com>
Subject RE: RequiredFields contents
Date Fri, 06 Nov 2009 06:24:07 GMT
The first element in the pair is the input number. Its mostly 0 for most
operators. For multi-input operators like join and cogroup, it will
range from 0 to (n - 1) where  n is the number of inputs.

Santhosh

-----Original Message-----
From: Dmitriy Ryaboy [mailto:dvryaboy@gmail.com] 
Sent: Thursday, November 05, 2009 9:05 PM
To: pig-dev@hadoop.apache.org
Subject: RequiredFields contents

Hi all,

I am looking at the RequiredFields class and it has this explanation of
what getFields() returns:

    /**
     * List of fields required from the input. This includes fields that
are
     * transformed, and thus are no longer the same fields. Using the
example 'B
     * = foreach A generate $0, $2, $3, udf($1)' would produce the list
(0, 0),
     * (0, 2), (0, 3), (0, 1). Note that the order is not guaranteed.
     */


The second element of the pair is self-explanatory -- but what is the
first element in the pair?

Thanks,
-Dmitriy

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