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Posted to issues@spark.apache.org by "Sun Rui (JIRA)" <ji...@apache.org> on 2016/01/20 08:42:39 UTC

[jira] [Updated] (SPARK-12919) Implement dapply() on DataFrame in SparkR

     [ https://issues.apache.org/jira/browse/SPARK-12919?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Sun Rui updated SPARK-12919:
----------------------------
    Description: 
dapply() applies an R function on each partition of a DataFrame and returns a new DataFrame.

The function signature is:
{code}
	dapply(df, function(localDF) {}, schema = NULL)
{code}

R function input: local data.frame from the partition on local node
R function output: local data.frame

Schema specifies the Row format of the resulting DataFrame. It must match the R function's output.

If schema is not specified, each partition of the result DataFrame will be serialized in R into a single byte array. Such resulting DataFrame can be processed by successive calls to dapply() or collect(), but can't be processed by normal DataFrame operations.



  was:
dapply() applies an R function on each partition of a DataFrame and returns a new DataFrame.

The function signature is:
{code}
	df <- dapply(df, function(localDF) {}, schema = NULL)
{code}

R function input: local data.frame from the partition on local node
R function output: local data.frame

Schema specifies the Row format of the resulting DataFrame. It must match the R function's output.

If schema is not specified, each partition of the result DataFrame will be serialized in R into a single byte array. Such resulting DataFrame can be processed by successive calls to dapply() or collect(), but can't be processed by normal DataFrame operations.




> Implement dapply() on DataFrame in SparkR
> -----------------------------------------
>
>                 Key: SPARK-12919
>                 URL: https://issues.apache.org/jira/browse/SPARK-12919
>             Project: Spark
>          Issue Type: Sub-task
>          Components: SparkR
>    Affects Versions: 1.6.0
>            Reporter: Sun Rui
>
> dapply() applies an R function on each partition of a DataFrame and returns a new DataFrame.
> The function signature is:
> {code}
> 	dapply(df, function(localDF) {}, schema = NULL)
> {code}
> R function input: local data.frame from the partition on local node
> R function output: local data.frame
> Schema specifies the Row format of the resulting DataFrame. It must match the R function's output.
> If schema is not specified, each partition of the result DataFrame will be serialized in R into a single byte array. Such resulting DataFrame can be processed by successive calls to dapply() or collect(), but can't be processed by normal DataFrame operations.



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