Algorithm for joining e.g. an array of strings

Question

I have wondered for some time, what a nice, clean solution for joining an array of strings might look like. Example: I have [\"Alpha\", \"Beta\", \"Gamma\"] and want to join

Answer 1

I usually go with something like...

list = ["Alpha", "Beta", "Gamma"];
output = "";
separator = "";
for (int i = 0; i < list.length ; i++) {
  output = output + separator;
  output = output + list[i];
  separator = ", ";
}

This works because on the first pass, separator is empty (so you don't get a comma at the start, but on every subsequent pass, you add a comma before adding the next element.

You could certainly unroll this a little to make it a bit faster (assigning to the separator over and over isn't ideal), though I suspect that's something the compiler could do for you automatically.

In the end though, I suspect pretty this is what most language level join functions come down to. Nothing more than syntax sugar, but it sure is sweet.