simpler

simpler (“simple R”) is a lightweight wrapper that calls R (really Rscript) from within ruby. It is designed to favor R in syntax.

Why use this rather than rsruby?

You should probably be using rsruby–it’s a fantastic gem. However, if you want to code using more of an R code sytax (e.g., to cut and paste R code and have it just work), or if you can’t get rsruby working, this gem may be useful to you.

Examples

FYI - the API is still a little unstable.

Basic execution (Raw input, raw output)

require 'simpler'

r = Simpler.new
r.eval! { "mean(c(1,2,3))" } # -> "[1] 2\n"  (a Simpler::Reply object)

Using ruby variables (calculating correlation coefficient):

x = [1,2,7]
y = [3,4,8]
reply = r.eval!(x,y) {|xr,yr|  "cor(#{xr},#{yr})"  }   # -> "[1] 0.9994238\n"

Any object that has a #to_r method can be passed in. Currently, Array and Simpler::DataFrame are the only objects with this method defined, but one can go really far with only these two data types.

Show a plot

Simpler uses Rscript to run R commands. So, all plots that would normally go to X11 are saved to “Rplots.pdf”. show! is precisly the same as eval!, but it also opens “Rplots.pdf” with @pdf_viewer:

r.pdf_viewer = "acroread"
r.show!(x,y) {|xr,yr| "plot(#{xr}, #{yr})" }

Using DataFrames

hash = {
  :one => [1,2,6,7],
  :two => [3,4,2,9],
  :three => [3,1,1,7],
}

df = Simpler::DataFrame.new(hash)
r.show!(df) {|dfr|  "plot(#{dfr})" }

One can also make a data frame from an array of structs with Simpler.from_structs

When Errors Arise

On an R error, raises a Simpler::RError that returns the R error message and shows the R code submitted. (the @command queue is still cleared)

r.eval! { "plot(c(1,2,3),c(1,2))" }

Credit

Simpler is loosely inspired by the original gnuplot and, of course, the excellent rsruby.

Casting

All replies are of class Simpler::Reply, so casting can be done in a way that works for you by defining your own methods.