[R] Preventing repeated package installation, or pre installing packages

Rainer Krug Rainer at krugs.de
Wed Nov 29 17:14:55 CET 2017

> On 29 Nov 2017, at 15:28, Larry Martell <larry.martell at gmail.com> wrote:
> I have a R script that I call from python using rpy2. It uses dplyr, doBy,
> and ggplot2. The script has install.packages commands for these 3 packages.
> Even thought the packages are already installed it still downloads,
> builds, and installs them, which is very time consuming. Is there a way to
> have it only do the install if the package is not already installed?

You could use something like

if (!require(dplyr)) {

where require() returns FALSE if it fails to load the package.

> Also, I run in a docker container, so after the container is instantiated
> the packages are not there the first time the script runs. Is there a way
> to pre load the packages, in which case I would not need the
> install.packages commands for these packages and my above question would
> become moot.

Yes - add them to you Docker file, but this is a docker question, not R. Check out the Rocker Dockerfiles to see how you can do this.


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Rainer M. Krug, PhD (Conservation Ecology, SUN), MSc (Conservation Biology, UCT), Dipl. Phys. (Germany)

University of Zürich

Cell:       +41 (0)78 630 66 57
email:      Rainer at krugs.de
Skype:      RMkrug

PGP: 0x0F52F982

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