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Pig >> mail # user >> Tuples in UDF and null


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Re: Tuples in UDF and null
good suggestion. Let me try that

On Thu, Mar 7, 2013 at 11:27 AM, Harsha <[EMAIL PROTECTED]> wrote:

> It will be easier if you have some sample data and run it through grunt
> shell.
> Lets say you have a dataset like this
> ({(1,)})
> ({(3,)})
> ({(5,10)})
> ({(7,)})
>
> some of them are nulls in your "b" and some rows has values for "b"
> and if you do a "generate" for above it will run through each row
> and try to fetch values for b if there is none it will do ()
> something like this
>
> ({()})
> ({()})
> ({(10)})
> ({()})
>
>
>
>
> --
> Harsha
>
>
> On Thursday, March 7, 2013 at 11:15 AM, Mohit Anchlia wrote:
>
> > sorry, yes my question was about accessing b not $1. What's the effect of
> > writing empty() to a file. Say if I did store b into temp then should I
> > expect a line or nothing gets writen at all in the file.
> >
> > On Thu, Mar 7, 2013 at 10:53 AM, Harsha <[EMAIL PROTECTED] (mailto:
> [EMAIL PROTECTED])> wrote:
> >
> > > from your schema b:bag{t:tuple(a:chararray, b:chararray)}
> > > your tuple is inside a bag so on the next line if you are trying to
> access
> > > through $1 pig will
> > > throw up an error saying non-existent column.
> > > but if your question is about accessing b than it will print empty ()
> if
> > > the there is no value present (as you are setting it as null).
> > >
> > > --
> > > Harsha
> > >
> > >
> > > On Thursday, March 7, 2013 at 10:35 AM, Mohit Anchlia wrote:
> > >
> > > > Thanks! Does "generate" skip over that? if I did b = for B generate
> $1
> > > what
> > > > should be expected outcome of alias "b"
> > > >
>  > > > On Thu, Mar 7, 2013 at 10:31 AM, Harsha <[EMAIL PROTECTED] (mailto:
> [EMAIL PROTECTED]) (mailto:
> > > [EMAIL PROTECTED] (mailto:[EMAIL PROTECTED]))> wrote:
> > > >
> > > > > Hi Mohit,
> > > > > it won't convert into string literal 'NULL' since its a tuple
> > > > > you'll see results like
> > > > > ('Hello',)
> > > > >
> > > > > --
> > > > > Harsha
> > > > >
> > > > >
> > > > > On Thursday, March 7, 2013 at 10:10 AM, Mohit Anchlia wrote:
> > > > >
> > > > > > Any help would be appreciated. I'll also write something shortly
> and
> > > see
> > > > > > what happens.
> > > > > >
> > > > > > On Wed, Mar 6, 2013 at 4:58 PM, Mohit Anchlia <
> > > [EMAIL PROTECTED] (mailto:[EMAIL PROTECTED])(mailto:
> > > > > [EMAIL PROTECTED] (mailto:[EMAIL PROTECTED]))>wrote:
> > > >
> > >
> > > > > >
> > > > > > > If I define and set tuple like this:
> > > > > > >
> > > > > > > Tuple t1 = mTupleFactory.newTuple(2);
> > > > > > > t1.set(0, "Hello");
> > > > > > > t1.set(1, NULL);
> > > > > > >
> > > > > > > and have schema like:
> > > > > > >
> > > > > > > b:bag{t:tuple(a:chararray, b:chararray)
> > > > > > >
> > > > > > > and then in the pig script if I do:
> > > > > > >
> > > > > > > page = foreach B generate b;
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > What should be expected outcome? Would "generate" convert NULL
> into
> > > > > > > literal 'NULL' as a string? Or does it skip over that NULL.
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> > >
> >
> >
> >
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