How to save a data frame as CSV to a user selected location using tcltk

Take a look at the write.csv or the write.table functions. You just have to supply the file name the user selects to the file parameter, and the dataframe to the x parameter:

write.csv(x=df, file="myFileName")

You need not to use even the package "tcltk". You can simply do as shown below:

write.csv(x, file = "c:\\myname\\yourfile.csv", row.names = FALSE)

Give your path inspite of "c:\myname\yourfile.csv".