Java flatMap vs C# SelectMany

• Old Java
  

  String[][] names = { { "John", "Mary", "Steven" }, { "Tom", "Jeff" } };
  List<String> list1 = new ArrayList<String>();  
  for (String[] s1 : names) {
      for (String s2 : s1) {
          list1.add(s2);
      }
  }
  

• Java 8 Stream API
  

  String[][] names = { { "John", "Mary", "Steven" }, { "Tom", "Jeff" } };
  List<String> list2 = Arrays.stream(names)
      .flatMap(s1 -> Arrays.stream(s1))
      .collect(Collectors.toList());
  

• C# LINQ (method syntax)
  

  string[][] names = { new string[] { "John", "Mary", "Steven" }, new string[] { "Tom", "Jeff" } };
  List<string> list3 = names.SelectMany(s1 => s1).ToList();
  

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