[R] Unable to update R 3.4 to R 3.5 in Ubuntu 18.04 LTS

[RUPJYOTI DAS]

Dear All,
I am using R to carry out RNA-Seq workflow in my standalone machine which
needs the latest R version >=3.5. I was trying to update firstly removing
the R 3.4 and reinstalling from scratch again the latest version. Can
anybody just guide me how to carry out the process as I am getting only R
3.4 again and again.
Also when I remove the
*deb ... bionic-cran35 (mirror for R cran )*

from the* source.list* file (opened by* sudo gedit /etc/apt/sources.list*)
the command *sudo apt-get update* works fine which does not upgrade the R
3.4 to R 3.5.1.
Adding the line
*deb ... bionic-cran35/ *
gives the attached error log*. **Please find the attached file and  do
check.*

Any answers and suggestions will be of immense help!

Thanking you!

*Rupjyoti Das*
*M.Tech*, Information Technology
Tezpur University
Assam, India 784028
Mob. +91-8812807195