Getting started¶

The RCall package is loaded via

julia> using RCall

This will initialize the R process in the background.

R"" string macro and rcopy¶

The simplest way to use RCall is via the R"" string macro:

julia> x = R"rnorm(10)"
RCall.RObject{RCall.RealSxp}
 [1]  2.14715927 -1.54768482 -2.15976616 -0.60222806  0.53387481 -1.00477140
 [7]  1.59695873 -0.05140429  0.87452673  0.64201625
R"

This evaluates the expression inside the string, and returns the result as an RObject, which is a Julia wrapper around an R object. This can be converted to a native Julia object via rcopy:

julia> rcopy(x)
10-element Array{Float64,1}:
  2.14716  
 -1.54768  
 -2.15977  
 -0.602228 
  0.533875 
 -1.00477  
  1.59696  
 -0.0514043
  0.874527 
  0.642016 

R's data.frame objects are automatically converted to Julia DataFrames:

julia> iris = rcopy(R"iris")
150x5 DataFrames.DataFrame
│ Row │ Sepal.Length │ Sepal.Width │ Petal.Length │ Petal.Width │ Species     │
┝━━━━━┿━━━━━━━━━━━━━━┿━━━━━━━━━━━━━┿━━━━━━━━━━━━━━┿━━━━━━━━━━━━━┿━━━━━━━━━━━━━┥
│ 1   │ 5.1          │ 3.5         │ 1.4          │ 0.2         │ "setosa"    │
│ 2   │ 4.9          │ 3.0         │ 1.4          │ 0.2         │ "setosa"    │
│ 3   │ 4.7          │ 3.2         │ 1.3          │ 0.2         │ "setosa"    │
...

The R"" macro also supports substitution of Julia objects via the $ symbol, whenever it is not valid R syntax (i.e. when not directly following a symbol such as aa$bb):

julia> R"lm(Sepal.Length ~ Sepal.Width + Species, data=$iris)"
RCall.RObject{RCall.VecSxp}

Call:
lm(formula = Sepal.Length ~ Sepal.Width + Species, data = `##RCall##1`)

Coefficients:
      (Intercept)        Sepal.Width  Speciesversicolor   Speciesvirginica  
           2.2514             0.8036             1.4587             1.9468