A Bit of Glue Between R and Stata.

RStata

A simple R -> Stata interface allowing the user to:

• execute Stata commands (both inline and from a .do file) from R;
• pass a data.frame to Stata;
• return a data.frame to R;
• include Stata 'chunks' in knitr documents (however each chunk is independent from the others; feature tested with LaTeX/Linux).

Install

install.packages('RStata')

Setup

In order to use this package you need to setup two options:

options("RStata.StataPath")
options("RStata.StataVersion")

Once done, the main function in the package is stata (see Examples below).

RStata.StataPath

RStata.StataPath contains the path to Stata executable (Windows user have to delete the extension .exe from the path ).

You can use

chooseStataBin()

to set this option the first time:

• in Linux it searches for the 4 (cli) Stata binaries (stata-mp, stata-se, stata, stata-sm) in the search path and prompt a menu to choose one;

• in Windows does a file.choose (and a bit of manipulation, in Windows, to obtain a valid path).

• other system are not handled by chooseStataBin (mainly because of my ignorance regarding both the system itself and Stata installation on it, but contributions are welcome).

  Mac users are a notable group: at this stage they should set the path for the command line executable (not the GUI app). Eg for a Stata13 SE installation in El Capitain (with default options) the path is '/Applications/Stata/StataSE.app/Contents/MacOS/stata-se'. In other cases (Stata licenses, installation path and so on) the path could be slightly different (BTW, i've found the path 'exploring' the filesystem with a terminal, not the graphics explorer since it 'stops' at 'StataSE.app').

chooseStataBin set up RStata.StataPath accordingly to user advice and return the path; but you may consider to put the path returned in .Rprofile options for the next time you start R.

RStata.StataVersion

RStata.StataVersion is needed for right management of data export/import to/from Stata. Eg, for Stata 13:

options("RStata.StataVersion" = 13)

As above, you may consider to put this statement in your .Rprofile.

Other options

See ?stata.

Troubleshooting

In some setup the package seems to freeze even with the simplest example (eg stata('set obs 10')). This is likely dued to Stata more option, which has to be set to off:

set more off, permanently

Examples

One inline command

> stata("help regress")  #<- this won't work in Windows dued to needed
                         #   batch mode

. help regress

Title
-----

    [R] regress -- Linear regression


Syntax
------

        regress depvar [indepvars] [if] [in] [weight] [, options]

[...]

Many inline commands

You can do this (eg.):

> stata_src <- "

version 10
sysuse auto
reg mpg weight

"
> stata(stata_src)

[...]

External .do file sourceing

> stata("foo.do")

Data input to Stata

> x <- data.frame(a = rnorm(3), b = letters[1:3])
> stata("sum a", data.in = x)

. sum a

   Variable |       Obs        Mean    Std. Dev.       Min        Max
------------+--------------------------------------------------------
          a |         3   -.5603985    .3000552  -.7720861  -.2170166

Data output from Stata

Eg in order to obtain auto dataset

> auto <- stata("sysuse auto", data.out = TRUE)

. sysuse auto
(1978 Automobile Data)
 
> head(auto)
           make price mpg rep78 headroom trunk weight length turn displacement
1   AMC Concord  4099  22     3      2.5    11   2930    186   40          121
2     AMC Pacer  4749  17     3      3.0    11   3350    173   40          258
3    AMC Spirit  3799  22    NA      3.0    12   2640    168   35          121
4 Buick Century  4816  20     3      4.5    16   3250    196   40          196
5 Buick Electra  7827  15     4      4.0    20   4080    222   43          350
6 Buick LeSabre  5788  18     3      4.0    21   3670    218   43          231
  gear_ratio  foreign
1       3.58 Domestic
2       2.53 Domestic
3       3.08 Domestic
4       2.93 Domestic
5       2.41 Domestic
6       2.73 Domestic

Data input/output

> x <- data.frame(a = rnorm(3), b = letters[1:3])
> (y <- stata("replace a = 2", data.in = x, data.out = TRUE))

. replace a = 2
(3 real changes made)

  a b
1 2 a
2 2 b
3 2 c

Contribute

You are welcome to:

• submit suggestions and bug-reports at: http://github.com/lbraglia/RStata/issues
• fork and send a pull request on: http://github.com/lbraglia/RStata/
• send an e-mail to: [email protected].