rxPartition: Partition Data by Key Values and Save the results to a Partitioned .Xdf

Article
07/15/2019

Description

Partition input data sources by key values and save the results to a partitioned Xdf on disk.

Usage

  rxPartition(inData, outData, varsToPartition, append = "rows", overwrite = FALSE, ...)

Arguments

`inData`

either a data source object, a character string specifying a .xdf file, or a data frame object.

`outData`

a partitioned data source object created by RxXdfData with createPartitionSet = TRUE.

`varsToPartition`

character vector of variable names to specify the values in those variables to be used for partitioning

`append`

either "none" to create a new files or "rows" to append rows to an existing file. If outData exists and append is "none", the overwrite argument must be set to TRUE.

`overwrite`

logical value. If TRUE, an existing outData will be overwritten. overwrite is ignored if append = "rows".

`...`

additional arguments to be passed directly to the Revolution Compute Engine.

Value

a data frame of partitioning values and data sources, each row in the data frame represents one partition and the data source in the last variable holds the data of a specifict partition.

Note

In the current version, this function is single threaded.

Author(s)

Microsoft Corporation Microsoft Technical Support

Examples



 ##############################################################################
 # Construct a partitioned Xdf
 ##############################################################################

   # create an input Xdf data source
   inFile <- "claims.xdf"
   inFile <- file.path(dataPath = rxGetOption(opt = "sampleDataDir"), inFile)
   inXdfDS <- RxXdfData(file = inFile)

   # create an output partitioned Xdf data source
   outFile <- file.path(tempdir(), "partitionedClaims.xdf")
   outPartXdfDataSource <- RxXdfData(file = outFile, createPartitionSet = TRUE)

   # construct and save the partitioned Xdf to disk
   partDF <- rxPartition(inData = inXdfDS, outData = outPartXdfDataSource, varsToPartition = c("car.age"))

 ##############################################################################
 # Append new data to an existing partitioned Xdf
 ##############################################################################

   # create two sets of data frames from Xdf data source
   inFile <- "claims.xdf"
   inFile <- file.path(dataPath = rxGetOption(opt = "sampleDataDir"), inFile)
   inXdfDS <- RxXdfData(file = inFile)
   inDF <- rxImport(inData = inXdfDS)

   df1 <- inDF[1:50,]
   df2 <- inDF[51:nrow(inDF),]

   # create an output partitioned Xdf data source
   outFile <- file.path(tempdir(), "partitionedClaims.xdf")
   outPartXdfDataSource <- RxXdfData(file = outFile, createPartitionSet = TRUE)

   # construct the partitioned Xdf from the first data set df1 and save to disk
   partDF1 <- rxPartition(inData = df1, outData = outPartXdfDataSource, varsToPartition = c("car.age", "type"), append = "none", overwrite = TRUE)

   # append data from the second data set to the existing partitioned Xdf
   partDF2 <- rxPartition(inData = df2, outData = outPartXdfDataSource, varsToPartition = c("car.age", "type"))

   # overwrite an existing partitioned Xdf
   partDF2 <- rxPartition(inData = inXdfDS, outData = outPartXdfDataSource, varsToPartition = c("car.age"), append = "none", overwrite = TRUE)

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