I'm trying to install R 4.0 on Ubuntu, but get this error:
$ sudo apt-get install r-base
Reading package lists... Done
Building dependency tree
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:
The following packages have unmet dependencies:
r-base : Depends: r-base-core (>= 4.0.0-1.2004.0) but it is not going to be installed
Depends: r-recommended (= 4.0.0-1.2004.0) but it is not going to be installed
Recommends: r-base-html but it is not going to be installed
E: Unable to correct problems, you have held broken packages.
I have run these commands to set up apt to receive R 4.0, as recommended at https://cran.r-project.org/bin/linux/ubuntu/README.html:
sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys E298A3A825C0D65DFD57CBB651716619E084DAB9
sudo add-apt-repository 'deb https://cloud.r-project.org/bin/linux/ubuntu focal-cran40/'
sudo apt-get update
What am I doing wrong, and how can I fix it?
I did have R 3.4 installed on this system before, and removed it with
sudo apt-get remove r-*
sudo apt-get purge r-*
Have I screwed something up by doing that?