However, when I implement the code, all I get is a file with a comma. Has there been changes to Julia since the answer was posted (April 6., 2018), which renders the answer inappropriate?
I would generally recommend using CSV.jl for writing and reading CSV data, since that has a lot more features and performance optimizations than DelimitedFiles. The latter works fine, if you just want to quickly write or read some data, but for anything more advanced, CSV.jl is definitely the way to go