Convert List of object to String[] with Lambda

Question

If I have a list of an example class User (shown below), can I create a String array for all the names in the list with one line using lambda?

class User{
  String name;
  int id;
}

khelwood · Accepted Answer · 2017-02-23 10:57:25Z

6

Yes. Given List<User> users:

String[] names = users.stream().map(user -> user.name).toArray(String[]::new);

That is "stream the users, get the name for each one, put them in a new String array."

If your User has a getName() method, then it would be:

String[] names = users.stream().map(User::getName).toArray(String[]::new);

answered Feb 23, 2017 at 10:57

khelwood

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