What questions have people used to work out whether someone is relative new to R vs an 'intermediate' R user vs an expert. Assume that they will be honest or have an interest in being streamed correctly. Naturally, anything beyond basic knowledge of R quickly becomes domain-specific, but I'd like to see how far we can get. I'm also concerned that I will mistake what I think is easy or hard with the order of knowledge that others learn.
Also particularly interested in scale, so questions that can be marked by people without R knowledge (or even by a computer) are great, whereas things that require a lot of subjective interpretation are less good.
Here are some of mine ordered roughly from easy to hard
- What is the function to install a new package in R?
- How do you open the help page for a function?
- Give two ways to access a column
- Write a line of R code that results in the error
non-numeric argument to binary operator
- Give an
x == yis
- Why does
- (From the R Inferno) Without running the code, what does the following return? Why?
> xr <- lapply(11:14, function(i) function() i^2) > sapply(1:4, function(j) xr[[j]]())