Where are the docs for the DataFrames by() function


I can’t find any docs for the by() function in DataFrames. There is an example of usage here, but no docs:



At the REPL, ?by works for me.


I guess the REPL is the only documentation. The REPL showed this which was helpful:

by(d, cols, f) is equivalent to combine(map(f, groupby(d, cols)))


Found this while searching for the DataFrames.nrow function: