The function downloads data provided by Kenneth
French at
http://mba.tuck.dartmouth.edu/pages/faculty/ken.french/data_library.html.
The download file gets a date prefix (current date in
format YYYYMMDD
) and is stored in directory
dest.dir
. Before any download is attempted,
the function checks whether a file with today's
prefix exist in dest.dir
; if yes, the file is
used.
In the original data files, missing values are
coded as -99
or similar. These
numeric values are replaced by NA
.
Calling the function without any arguments will print
the names of the supported datasets (and return them insivibly).