You can literally return a Python tuple of outputs from a composite
transform as well. (Dicts with PCollections as values are also
supported, if you want things to be named rather than referenced by
index.)

On Fri, Oct 25, 2019 at 4:06 PM Ahmet Altay <[email protected]> wrote:
>
> Is DoOutputsTuple what you are looking for? [1] You can look at this expand 
> function using it [2].
>
> [1] 
> https://github.com/apache/beam/blob/master/sdks/python/apache_beam/pvalue.py#L204
> [2] 
> https://github.com/apache/beam/blob/master/sdks/python/apache_beam/transforms/core.py#L1283
>
> On Fri, Oct 25, 2019 at 3:51 PM Luke Cwik <[email protected]> wrote:
>>
>> My example is about multiple inputs and not multiple outputs from further 
>> investigation it seems as I don't know.
>>
>> Looking at the documentation online[1] doesn't seem to specify how to do 
>> this either for composite transforms. All the examples are of the single 
>> output variety as well[2].
>>
>> 1: 
>> https://beam.apache.org/documentation/programming-guide/#composite-transforms
>> 2: 
>> https://github.com/apache/beam/blob/4ba731fe93f7f8385c771caf576745d14edf34b8/sdks/python/apache_beam/examples/cookbook/custom_ptransform.py
>>
>> On Fri, Oct 25, 2019 at 10:24 AM Luke Cwik <[email protected]> wrote:
>>>
>>> I believe PCollectionTuple should be unnecessary since Python has first 
>>> class support for tuples as shown in the example below[1]. Can we use 
>>> tuples to solve your issue?
>>>
>>> wordsStartingWithA = \
>>>     p | 'Words starting with A' >> beam.Create(['apple', 'ant', 'arrow'])
>>>
>>> wordsStartingWithB = \
>>>     p | 'Words starting with B' >> beam.Create(['ball', 'book', 'bow'])
>>>
>>> ((wordsStartingWithA, wordsStartingWithB)
>>>     | beam.Flatten()
>>>     | LogElements())
>>>
>>> 1: 
>>> https://github.com/apache/beam/blob/238659bce8043e6a64619a959ab44453dbe22dff/learning/katas/python/Core%20Transforms/Flatten/Flatten/task.py#L29
>>>
>>> On Fri, Oct 25, 2019 at 10:11 AM Sam Rohde <[email protected]> wrote:
>>>>
>>>> Talked to Daniel offline and it looks like the Python SDK is missing 
>>>> PCollection Tuples like the one Java has: 
>>>> https://github.com/rohdesamuel/beam/blob/master/sdks/java/core/src/main/java/org/apache/beam/sdk/values/PCollectionTuple.java.
>>>>
>>>> I'll go ahead and implement that for the Python SDK.
>>>>
>>>> On Thu, Oct 24, 2019 at 5:20 PM Sam Rohde <[email protected]> wrote:
>>>>>
>>>>> Hey All,
>>>>>
>>>>> I'm trying to implement an expand override with multiple output 
>>>>> PCollections. The kicker is that I want to insert a new transform for 
>>>>> each output PCollection. How can I do this?
>>>>>
>>>>> Regards,
>>>>> Sam

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