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From Josh Wills <jwi...@cloudera.com>
Subject Re: Joins and null values
Date Wed, 18 Feb 2015 22:53:05 GMT
Oh, I'm dumb-- you mean you want like a left-join like thing where you can
find all values in collection A that aren't in collection B, etc., etc.?

J

On Wed, Feb 18, 2015 at 2:43 PM, Josh Wills <jwills@cloudera.com> wrote:

> Different from o.a.c.lib.Cartesian.cross(PCollection<U> left,
> PCollection<T> right, int parallelism) in some way?
>
> J
>
> On Wed, Feb 18, 2015 at 2:41 PM, Bryan Baugher <bjbq4d@gmail.com> wrote:
>
>>
>> Maybe,
>>
>> PCollection<T>#join(PCollection<T>, JoinType) : PCollection<Pair<T,
T>>
>>
>> You could make additional methods for the different join strategies or
>> maybe an enum perhaps?
>>
>> On Wed Feb 18 2015 at 3:58:38 PM Josh Wills <jwills@cloudera.com> wrote:
>>
>>> Hey Bryan,
>>>
>>> I like the idea of throwing exceptions when there are null values in one
>>> of the collections in a join. Not sure if there are any other implications
>>> of that I should think through first.
>>>
>>> On the convenience methods for PCollection joins, what do you have in
>>> mind?
>>>
>>> J
>>>
>>>
>>> On Wed, Feb 18, 2015 at 12:35 PM, Bryan Baugher <bjbq4d@gmail.com>
>>> wrote:
>>>
>>>> Hi everyone,
>>>>
>>>> The other day I ran into the issue mentioned here[1] about joining data
>>>> with null values. This took awhile to figure out until I broke down and
>>>> went to look at the docs to see if I was doing something obviously wrong.
I
>>>> used null values because I'm basically wanting to join two pcollections.
>>>>
>>>> Can crunch either throw an exception or log errors if I do something
>>>> like this? Similarly would it be possible to get convenience methods for
>>>> doing joins on PCollections?
>>>>
>>>> [1] - http://crunch.apache.org/user-guide.html#joins
>>>>
>>>
>>>
>>>
>>> --
>>> Director of Data Science
>>> Cloudera <http://www.cloudera.com>
>>> Twitter: @josh_wills <http://twitter.com/josh_wills>
>>>
>>
>
>
> --
> Director of Data Science
> Cloudera <http://www.cloudera.com>
> Twitter: @josh_wills <http://twitter.com/josh_wills>
>



-- 
Director of Data Science
Cloudera <http://www.cloudera.com>
Twitter: @josh_wills <http://twitter.com/josh_wills>

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