[jira] [Updated] (SPARK-19492) Dataset, map, 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:all-tabpanel ]

Loic Descotte updated SPARK-19492:
----------------------------------
    Description: 
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 on Scala collections filter function for example.


  was:
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}

I don't know why it's not working, unlike Scala collections filter function for example.



> Dataset, map, 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
>
> 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 on Scala collections filter function for example.



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