Comment by jonnycomputer

A lot of this is personal aesthetics, for sure. Personally, I am not a big fan of camel casing. In code, I only use it for class names, generally. I don't find it particularly readable, and for filenames, not all filesystems are case sensitive, so best not to rely on case to differentiate files. Camel case does have the nice property of being more compact, as no character is required. That's its main benefit.

R traditionally uses the . as a legal character in identifiers. Once you get it used to not being syntactic, I found I actually prefer them to underscores.