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资源说明：simpler ("Simple R") is a lightweight wrapper of R (really Rscript) inspired by the gnuplot and rsruby gems.
= simpler
simpler ("simple R") is a lightweight wrapper that calls R (really Rscript)
from within ruby. It is designed to favor R in syntax.
This is still very pre-alpha and the interface is subject to change.
=== RSRuby, RinRuby, or Simpler?
You should probably take a look at rsruby--it's a fantastic gem. Embedding R,
rather than calling out to R can make calls 10X faster (according to {Ryan
Davis}[http://www.ruby-forum.com/topic/670136#969929]). Plus, if you need to
evaluate R code with rsruby, you can use this kind of call:
RSRuby.instance.eval_R r_src
However, if you want to work with a system designed for using native R code,
or if you can't get rsruby compiling properly, RinRuby or Simpler may be
useful to you.
RinRuby[https://sites.google.com/a/ddahl.org/rinruby-users/] has the same
design goals as Simpler and is much more thorough in its implementation and
execution. You should definitely take a look at RinRuby.
Simpler is very simple code that uses Rscript (R's scripting command) to plot
R code. If a robust, minimalist approach appeals to you, maybe simpler is for
you. I like to use it when I'm not using RSRuby or RinRuby.
== Examples
(the API is still unstable)
==== Basic execution (Raw input, raw output)
require 'simpler'
r = Simpler.new
r >> "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]
# variables are given a symbol name
reply = r.eval!(x => :xr, y => :yr) { "cor(xr,yr)" } # -> "[1] 0.9994238\n"
# the naming can be in any order, so in ruby > 1.9, this is valid:
reply = r.eval!(xr: x, yr: y) { "cor(xr,yr)" }
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 that
actually covers a lot of ground. Easy to define your own to_r method for
special data as needed.
==== 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::DataFrame.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)
# this will raise a descriptive Simpler::RError error
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. I ran into RinRuby after writing Simpler: I probably
wouldn't have written Simpler had I seen it first, but since it is here and
since it has a slightly different design and implementation I will continue to
support it.
==Casting
All replies are of class Simpler::Reply (a string subclass), so casting can be
done in a way that works for you by defining your own methods.
== Copyright
Copyright (c) 2010 John Prince. See LICENSE for details.
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