Thanks very much for the suggestion koert. Yes, this does the trick for me.
However, as you mentioned I won't have access to the field names which I
guess is fine. For the scenario that I explained, I can just check the
tuple elements and see if they are of type List or not, if they are I will
invoke the method I want, otherwise I won't touch their values.
Thanks again!
On Friday, June 30, 2017 at 5:01:30 PM UTC-7, koert wrote:
>
> you can do an operation on all fields along the lines of:
>
> import cascading.tuple.{ Tuple => CTuple }
> pipe.map(Fields.ALL -> Fields.ARGS){ (ctuple: CTuple) => ... }
>
> however this does not give you access to the field names
>
> On Fri, Jun 30, 2017 at 5:13 PM, <[email protected] <javascript:>> wrote:
>
>> Here is the question:
>>
>> Assume I have a pipe and I want to rename all the fields in the pipe
>> programmatically, meaning that I don't want to hard code the field names in
>> my code. Any idea how I can do this?
>>
>> As a concrete example, assume I have a pipe with two fields: "name" and
>> "age" and I want to rename these fields to "employee_name" and
>> "employee_age". Obviously the natural solution is to write a piece of code
>> as below:
>>
>> pipe.rename(('name, 'age) -> ('employee_name, 'employee_age))
>>
>> or
>>
>> pipe.rename(new Fields("name", "age") -> new Fields("employee_name",
>> "employee_age"))
>>
>> However, what I need is to be able to iterate through all fields in the
>> pipe without knowing their names.
>>
>> There are a couple of methods (resolveIncomingOperationArgumentFields and
>> resolveIncomingOperationPassThroughFields) callable on a pipe which look
>> promising but the issue is that they both take and input argument of type
>> cascading.flow.planner.Scope which I don't know where can I get it from in
>> a scalding job.
>>
>> Another solution that comes to my mind is using "each" method on the pipe
>> and implementing a cascading function and pass it to the each statement.
>> But I was now able to find any sample code for that either.
>>
>> Thanks!
>>
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