[.Net] 以string,Join串接array of array(jagged array)

大家都知道使用string.Join可以串接陣列或清單中字串，像是下面這樣的形式

string[] source = new string[]{"one", "two", "three"};
string result = string.Join(",", source);

但是當陣列中還有陣列(jagged array, e.g. array of array)的時候怎麼辦呢？
這時候LINQ的Select語法就派上用場了，一層一層的串上去就對了

string[][][] source = new string[][][]{
 new string[][]{
  new string[]{"1", "2", "3"},
  new string[]{"one", "two", "three"}
 },
 new string[][]{
  new string[]{"4", "5", "6"},
  new string[]{"five", "six", "seven"}
 }
};

string result = string.Join(",", source.Select(m => string.Join(",", m.Select(n => string.Join(",", n)))));

如此一來就可以成功串接每一層陣列中的字串了。

Reference:
https://stackoverflow.com/questions/35102320/c-sharp-copying-jagged-arrays-to-strings