After building 10,742 packages on Launchpad, I would like announce that cran2deb4ubuntu3.5 (c2d4u3.5 for short) is now available for testing and maybe even actually use. It wasn’t difficult to find if you know your way around launchpad, but you can find the PPA here: https://launchpad.net/~marutter/+archive/ubuntu/c2d4u3.5 Many things to consider before you add this PPA to your Ubuntu machine. The PPA supplies binaries for Trusty (14.04), Xenial (16.04), and Bionic (18.
One of the advantages of using Launchpad’s PPA system is that it allows you to easily use the work of others backporting packages to older releases. For example, the package jgr has a build requirement of libjq. jq is a command-line JSON processor, and the jqr package is required by a small number of other R packages, either directly or indirectly. The Ubuntu packages libjq-dev is available in Bionic, but not be default in Trusty or Xenial.
One of the research projects I have been working on for many years is a model that predicts E. coli levels at Presque Isle State Park beaches in Erie, PA. Presque Isle State Park brings in approximately 4.5 million visitors a year, and thanks to the Pennsylvania State Park system, is 100% free to use. A variety of different tools are used to protect swimmers from harmful bacteria, including my random forest model RoboHarry, named after the former lead ranger at the park.
I am slowly rebuilding the set of packages in c2d4u for use with R 3.5.0. Since packages built under version 3.4.* are not compatible with 3.5.0, they all need to be rebuilt. This includes the packages that came with the new Ubuntu Bionic (18.04) release. It is taking some time. One of the challenges with using Launchpad is that once a package is built, it needs to be published. This takes some time (around 20 minutes).