JuliaConnectoR (version 1.1.4)

as.data.frame.JuliaProxy: Coerce a Julia Table to a Data Frame

Description

Get the data from a Julia proxy object that implements the Julia Tables interface, and create an R data frame from it.

Usage

# S3 method for JuliaProxy
as.data.frame(x, ...)

Arguments

x

a proxy object pointing to a Julia object that implements the interface of the package Julia package Tables

...

(not used)

Details

Strings are not converted to factors.

Examples

# \dontshow{
   if (juliaSetupOk() && Sys.getenv("NOT_CRAN") == "true") {
      Pkg <- juliaImport("Pkg")
      if (juliaEval('VERSION < v"1.6"')) {
         subproject <- "1_0"
      } else if (juliaEval('VERSION < v"1.10"')) {
         subproject <- "1_6"
      } else {
         subproject <- "1_10"
      }
      Pkg$activate(system.file("examples", "IndexedTables-Project", subproject,
                   package = "JuliaConnectoR"))
      Pkg$instantiate()
      # ignore warnings on Julia 1.0:
      capture.output(juliaImport("IndexedTables"), type = "message")
   }
# }
if (juliaSetupOk() && Sys.getenv("NOT_CRAN") == "true") {
   # (This example is not run on CRAN as it takes a little too long.)

   # Demonstrate the usage with the Julia package "IndexedTables" (v1.0)

   # Install the package first if it is not installed:
   # juliaEval('import Pkg; Pkg.add("IndexedTables")')

   # Import "IndexedTables" package
   IndexedTables <- juliaImport("IndexedTables")

   mydf <- data.frame(x = c(1, 2, 3),
                      y = c("a", "b", "c"),
                      z = c(TRUE, FALSE, NA),
                      stringsAsFactors = FALSE)

   # Create a table in Julia, e. g. via IndexedTables
   mytbl <- IndexedTables$table(mydf)

   # This table can, e g. be queried and
   # the result can be translated to an R data frame.
   seltbl <- IndexedTables$select(mytbl, juliaExpr("(:x, :y)"))[1:2]

   # Translate selection of Julia table into R data frame
   as.data.frame(seltbl)

}

# \dontshow{
   if (juliaSetupOk() && Sys.getenv("NOT_CRAN") == "true") {
      rm(mytbl, seltbl)
      JuliaConnectoR:::stopJulia()
   }
# }