How come Sololearn does not have anything on data vizualization? R or Julia?

Question

I would like to learn more

Answer 1

I would gues that there are at least two reasons:
1. They are really cpecific languages, and not interesting for most people who start learning programming.
2. To be able try some examples you need to somehow store data. I think that it is not as easy as create online compiler for other languages. (as you can see solelearn have SQL cource, but no code playground)