Learn R programming

(it has basic understanding of r-programming)

https://www.educba.com/r-studio-function/

(Code properties for R programming about how to write a code in R)

https://google.github.io/styleguide/Rguide.xml

(tutorial for r-programming)

https://www.tutorialspoint.com/r/index.htm

tips and tricks in r-programming

https://www.youtube.com/watch?v=kuSQgswZdr8

(has all functions in r programming)

https://www.guru99.com/r-replace-missing-values.html

(How to do data manipulation using filters)

https://www.datanovia.com/en/lessons/subset-data-frame-rows-in-r/

https://www.r-bloggers.com/5-ways-to-subset-a-data-frame-in-r/