I am wondering if there's a one-line way of copying an array to a list than the following:
String array[] = new String[]{"1", "2", "3", "4" } ;
List list = new ArrayList();
for (int i=0; i< array.length; i++){
list.add(array[i] );
}
Edit: thanks for both informative answers, very helpful :)
Yes there is a one liner, use Arrays.asList(T...a) to convert an array into list and pass it as an argument into the ArrayList overloaded constructor which takes a Collection.
List<String> list = new ArrayList<String>(Arrays.asList(array))
List<E> is an interface, so you cannot instantiate it. Maybe you meant new ArrayList<String>()?
If you need the array in list format but do not actually need to modify structurally the array you can do: List<String> list = Arrays.asList(array);.
Otherwise the answer of@PremGenError is the one to go for.
Arrays.asList() and the creation of a new list altogether.The simplest approach is:
List<String> fixedList = Arrays.asList(array);
However this will return a fixed-size list backed by the specified array.
This means that an attempt to modify the list (such as list.add("10"))
will result in a java.lang.UnsupportedOperationExceptionat run-time - so be careful.
A modifiable list can be constructed based on the fixed-size list:
List<String> modifiableList = new ArrayList<String>(fixedList);
Both steps can be amalgamated into a single line of code, like so:
List<String> list = new ArrayList<String>(Arrays.asList(array));
List. Also,List<E>is an interface, so it cannot be instantiated: you may create anArrayList<E>or aLinkedList<E>instead.List<String>.