[jira] [Comment Edited] (SPARK-19492) Dataset, filter and pattern matching on elements

["Loic Descotte (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/SPARK-19492?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15856208#comment-15856208 ] 

Loic Descotte edited comment on SPARK-19492 at 2/7/17 3:48 PM:
---------------------------------------------------------------

[~srowen] It's normal, in your example the compiler can't find the type by itself. But when the structure is typed, like a Seq[T], it should work. As it's working for RDD and all scala collections, I don't think there is a special magic in Seq. 
More explanations here : http://stackoverflow.com/a/12869583/591922

Edit : Just figured out that it actually works with map, but not filter


was (Author: loicd):
[~srowen] It's normal, in your example the compiler can't find the type by itself. But when the structure is typed, like a Seq[T], it should work. As it's working for RDD and all scala collections, I don't think there is a special magic in Seq. 
More explanations here : http://stackoverflow.com/a/12869583/591922

> Dataset, filter and pattern matching on elements
> ------------------------------------------------
>
>                 Key: SPARK-19492
>                 URL: https://issues.apache.org/jira/browse/SPARK-19492
>             Project: Spark
>          Issue Type: Bug
>          Components: SQL
>    Affects Versions: 2.0.2, 2.1.0
>            Reporter: Loic Descotte
>            Priority: Minor
>
> It seems it is impossible to use pattern matching to define input parameters for functions like filter, map, etc. on datasets.
> Example :
> This one is working :
> {code}
> val departments = Seq(
>     Department(1, "hr"),
>     Department(2, "it")
> ).toDS
> departments.filter{ d=> 
>   d.name == "hr"
> }
> {code}
> but not this one :
> {code}
>  departments.filter{ case Department(_, name)=>
>   name == "hr"
> }
> {code}
> Error :
> {code}
> error: missing parameter type for expanded function
> The argument types of an anonymous function must be fully known. (SLS 8.5)
> Expected type was: ?
>     departments.filter{ case Department(_, name)=>
> {code}
> This kind of pattern matching should work (as departements dataset type is known) like Scala collections filter function, or RDD filter function for example.



--
This message was sent by Atlassian JIRA
(v6.3.15#6346)

---------------------------------------------------------------------
To unsubscribe, e-mail: issues-unsubscribe@spark.apache.org
For additional commands, e-mail: issues-help@spark.apache.org