Dada una Colección con algunos valores, la tarea es agregar todos los elementos de esta Colección a una ArrayList en Java.
Ilustraciones:
Input: Collection = [1, 2, 3] Output: ArrayList = [1, 2, 3]
Input: Collection = [GFG, Geek, GeeksForGeeks] Output: ArrayList = [GFG, Geek, GeeksForGeeks]
Acercarse:
- Obtenga la colección cuyos elementos se agregarán a ArrayList
- Crear una lista de arreglos
- Agregue todos los elementos de la colección a este ArrayList usando el método ArrayList.addAll()
- Se ha creado ArrayList con todos los elementos de Colecciones.
Ejemplo
Java
// Java Program to Add All Items from a collection
// to an ArrayList
// Importing required classes
import java.io.*;
import java.util.*;
import java.util.stream.*;
// Main class
class GFG {
// Method 1
// To add all items from a collection
// to an ArrayList
public static <T> ArrayList<T>
createArrayList(List<T> collection)
{
// Creating an ArrayList
ArrayList<T> list = new ArrayList<T>();
// Adding all the items of Collection
// into this ArrayList
list.addAll(collection);
return list;
}
// Method 2
// Main driver method
public static void main(String[] args)
{
// Getting array elements as list
// and storing in a List object
List<Integer> collection1 = Arrays.asList(1, 2, 3);
// Printing elements in above List object
System.out.println("ArrayList with all "
+ "elements of collection "
+ collection1 + ": "
+ createArrayList(collection1));
// Again creating another List class object
List<String> collection2 = Arrays.asList(
"GFG", "Geeks", "GeeksForGeeks");
// Printing elements in above List object
System.out.println("ArrayList with all"
+ " elements of collection "
+ collection2 + ": "
+ createArrayList(collection2));
}
}
Producción
ArrayList with all elements of collection [1, 2, 3]: [1, 2, 3] ArrayList with all elements of collection [GFG, Geeks, GeeksForGeeks]: [GFG, Geeks, GeeksForGeeks]