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Pig, mail # user - Subtracting contents of two bags


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James Newhaven 2013-01-22, 12:46
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Bill Graham 2013-01-22, 15:53
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Re: Subtracting contents of two bags
Timothy Potter 2013-01-22, 16:36
Bill's suggestion is good, but here is another approach that I think is
cleaner to read:

find_not_in_b = cogroup A by key OUTER, B by key;
not_in_b = foreach (filter find_not_in_b by IsEmpty(B)) generate flatten(A);
On Tue, Jan 22, 2013 at 8:53 AM, Bill Graham <[EMAIL PROTECTED]> wrote:

> You can do an left outer join of A and B and then filter by B is null.
>
> http://pig.apache.org/docs/r0.10.0/basic.html#join-outer
>
> On Tue, Jan 22, 2013 at 4:46 AM, James Newhaven <[EMAIL PROTECTED]
> >wrote:
>
> > Hi,
> >
> > I have two relations - A and B.  Both just contain user ids.
> >
> > I want to get a list of users who are in A but not in B.
> >
> > I am running Pig 0.9.1 and think this might be possible with the DIFF
> > function. I can see that DIFF requires one relation that contains the two
> > bags.
> >
> > How can I create a relation that contains two bags so it can be supplied
> to
> > the DIFF function?
> >
> > Any suggestions would be appreciated.
> >
> > Thanks,
> > James
> >
>
>
>
> --
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