spark_apply

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Apply an R Function in Spark

Applies an R function to a Spark object (typically, a Spark DataFrame).

Usage
spark_apply(x, f, columns = colnames(x), memory = TRUE, group_by = NULL,
  packages = TRUE, ...)
Arguments
x

An object (usually a spark_tbl) coercable to a Spark DataFrame.

f

A function that transforms a data frame partition into a data frame. The function f has signature f(df, group1, group2, ...) where df is a data frame with the data to be processed and group1 to groupN contain the values of the group_by values. When group_by is not specified, f takes only one argument.

columns

A vector of column names or a named vector of column types for the transformed object. Defaults to the names from the original object and adds indexed column names when not enough columns are specified.

memory

Boolean; should the table be cached into memory?

group_by

Column name used to group by data frame partitions.

packages

Boolean to distribute .libPaths() packages to each node, a list of packages to distribute, or a package bundle created with spark_apply_bundle().

For clusters using Livy or Yarn cluster mode, packages must point to a package bundle path created using spark_apply_bundle() and made available as a Spark file. For Yarn cluster mode, the bundle can be registered as a Spark file using config$sparklyr.shell.files. For Livy, this bundle must be copied into the cluster and then made available using invoke(spark_context(sc), "addFile", "<path-to-file>").

For offline clusters where available.packages() is not available, manually download the packages database from https://cran.r-project.org/web/packages/packages.rds and set Sys.setenv(sparklyr.apply.packagesdb = "<pathl-to-rds>"). Otherwise, all packages will be used by default.

...

Optional arguments; currently unused.

Aliases
  • spark_apply
Documentation reproduced from package sparklyr, version 0.6.4, License: Apache License 2.0 | file LICENSE

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