How would I return a list of values?
(val1, val2, val3...)
I tried returning a List<Object> however it I get a tuple that contains
a tuple with a list of values and I have to flatten it to get the
desired behavior.
((val1, val2, val3...))
Thanks
On 4/1/11 10:09 AM, Dmitriy Ryaboy wrote:
Right, Pig always returns a Tuple that contains whatever your UDF returns --
so if you return a string, it returns a Tuple with a String in it.
Unfortunately that also means that if you return a Tuple, you get a Tuple in
a Tuple.
We probably shouldn't do that, but at this point changing the behavior can
break a lot of people's existing pig code :(.
D
On Fri, Apr 1, 2011 at 7:30 AM, Mark<[email protected]> wrote:
I created the following:
http://pastie.org/1743857
And I'm using it in the following way:
register 'target/pig-1.0-SNAPSHOT.jar'
rows = LOAD 'foo' AS (user:chararray, item:long);
grouped = GROUP rows BY user;
final = GENERATE FLATTEN(com.mycompany.pig.udf.Foo(unique.item));
Does that look about right? Is there any particular reason why I need to
flatten at the end? When I try to output a simple tuple from the EvalFunc it
is always a tuple inside a tuple.
Thanks
On 3/31/11 10:10 AM, Jonathan Coveney wrote:
You definitely can do this with a UDF. You simply take the Tuples as input
and then begin concatenating them together. Be wary of memory limitations
for the intermediate as it gets large. It may be more practical to let the
output be a tuple whose element sare the rows.
(199027860,199027860,149167529,203508790,198488630)
then the input to your UDF will be a tuple whose first element is a bag,
and
then the output will be a tuple of all the elements. It is quite easy to
write something that does this, take a look at the UDF documentation and
ask
if you need any help.
2011/3/31 Mark<[email protected]>
I have these "rows"
({(155495400)})
({(199027860),(199027860),(149167529),(203508790),(198488630)})
({(174255619),(201077556),(199051606),(198778302)})
I believe the correct way to explain them would be each row/tuple is a
bag
that contains tuples of size 1? Is that right?
Anyway, is there something native or UDF I can use to convert them to
this
format?
(155495400)
(199027860 199027860 149167529 203508790 198488630)
(174255619 201077556 199051606 198778302)
Maybe if I explain what we are trying to do it would help.
We have logs of users to product views in a tab delimited format.
foo\t1234
bar\t1234
foo\t4423
baz\t5563
We simply want product views grouped by user and outputed on 1 line.
1234 4423
1234
5563
The above first line would be from the user foo, second bar and third
baz.
Thanks
