JAVA
How to convert Arrays to List
seoca
2019. 2. 26. 01:39
1. Arrays.asList() method makes the original array available as a list.
Example code
public class Main{
public static void main(String[] args) {
String[] fruit_array = new String[]{"apple","banana","mango"};
List<String> fruit_list = Arrays.asList(fruit_array);
//returned List is fixed size
fruit_list.add("melon"); //Error
fruit_list.remove(0); //Error
fruit_list.set(1,"kiwi");
System.out.println(fruit_list); //[apple, kiwi, mango]
}
}
2. Using List Constructor enables some kind of operations to change the List.
Example code
public class Main{
public static void main(String[] args) {
String[] fruit_array = new String[]{"apple","banana","mango"};
//Constructor
List<String> fruit_list = new ArrayList<>(Arrays.asList(fruit_array));
//you can do every operations on the List
fruit_list.add("melon");
fruit_list.remove(0);
fruit_list.set(1,"kiwi");
System.out.println(fruit_list); //[banana, kiwi, melon]
}
}
3. Collection API
Example code I
public class Main{
public static void main(String[] args) {
String[] fruit_array = new String[]{"apple","banana","mango"};
List<String> fruit_list = new ArrayList<>(fruit_array.length);
Collections.addAll(fruit_list,fruit_array);
System.out.println(fruit_list); //[apple, banana, mango]
}
}
Example code II
public class Main{
public static void main(String[] args) {
String[] fruit_array = new String[]{"apple","banana","mango"};
List<String> fruit_list = new ArrayList<>(Arrays.asList(fruit_array));
String[] another_array = new String[]{"add1","add2"};
Collections.addAll(fruit_list,another_array);
System.out.println(fruit_list); //[apple, banana, mango, add1, add2]
}
}
Reference
https://www.youtube.com/watch?v=_ntIzftXKMM