R has probably the best help feature for any language -- not only can you ask it about help on individual functions with "?", the tradition (and this continues

R has probably the best help feature for any language -- not only can you ask it about help on individual functions with "?", the tradition (and this continues with most add in packages as well as builtins) is not only does it give you info on the function, it gives you example code using it so you can understand what it does in practice.