Python is a general-purpose programming language for data scientists to collect, clean, and analyse data. It is often used because it is flexible and suitable for handling large datasets. 
R is a free, user developed, advanced statistical and computing programme for statistical computing and graphics. It is increasingly used in the academic world for teaching purposes. 
R provides a wide variety of statistical (linear and nonlinear modelling, classical statistical tests, time-series analysis, classification, clustering, …) and graphical techniques, and is highly extensible.
One of R’s strengths is the ease with which well-designed publication-quality plots can be produced, including mathematical symbols and formulae where needed. Great care has been taken over the defaults for the minor design choices in graphics, but the user retains full control. r-project.org