when to omit comma separators

cofv<- function(x) sd(x)/mean(x) There is no comma in this argument, and this is one thing that confuses me: Sometimes there is a comma to separate 开发者_StackOverflow中文版arguments, sometimes there isn’t. How is it determined whether I need a comma?

There is only one argument, 'x'. You need to show other examples where there are commas that you don't understand. the function could be written:

cofv<- function(x) {
          sd(x)/mean(x) }