Which is better for a beginner: R or Python?
It's a perennial debate. Python is more readable and quicker to learn, no question. It's also a bit more general-purpose language than R. R, on the other hand, has special statistical packages for just about anything you could even dream of doing. There are some stats it can do that Python doesn't have a library for (though I suspect people are working on that). 

What's more important in the early stages of learning data science is the more fundamental theory: mathematics, linear algebra, calculus, and statistics. A firm grasp of those areas is a considerably larger share of the learning path than a particular language.

Having said that, I do happen to prefer Python because of the readability. The fact is, that very often other people will need to come in after you and read what you wrote. For that matter, you sometimes have to read your own code! Readability is more important than the ability to do fantastic things with one-liners. As for the advanced stats, that comes into play most often in the medical fields; there you definitely find a preponderance of R over Python.