spark-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Koert Kuipers <ko...@tresata.com>
Subject Re: frustration with field names in Dataset
Date Thu, 02 Feb 2017 19:29:09 GMT
great its an easy fix. i will create jira and pullreq

On Thu, Feb 2, 2017 at 2:13 PM, Michael Armbrust <michael@databricks.com>
wrote:

> That might be reasonable.  At least I can't think of any problems with
> doing that.
>
> On Thu, Feb 2, 2017 at 7:39 AM, Koert Kuipers <koert@tresata.com> wrote:
>
>> since a dataset is a typed object you ideally don't have to think about
>> field names.
>>
>> however there are operations on Dataset that require you to provide a
>> Column, like for example joinWith (and joinWith returns a strongly typed
>> Dataset, not DataFrame). once you have to provide a Column you are back to
>> thinking in field names, and worrying about duplicate field names, which is
>> something that can easily happen in a Dataset without you realizing it.
>>
>> so under the hood Dataset has unique identifiers for every column, as in
>> dataset.queryExecution.logical.output, but these are expressions
>> (attributes) that i cannot turn back into columns since the constructors
>> for this are private in spark.
>>
>> so.... how about having Dataset.apply(i: Int): Column to allow me to pick
>> columns by position without having to worry about (duplicate) field names?
>> then i could do something like:
>>
>> dataset.joinWith(otherDataset, dataset(0) === otherDataset(0), joinType)
>>
>
>

Mime
View raw message