检查元素是否在List中检查元素是否在List中

import java.util.ArrayList;
【检查元素是否在List中】public class ExistanceForList {

public static void main(String[] args) { // TODO Auto-generated method stub // create a new ArrayList of Strings with an initial capacity of 10 ArrayList items = new ArrayList(); items.add("red"); // append an item to the list items.add(0, "yellow"); // insert "yellow" at index 0// check if a value is in the List System.out.printf("\"red\" is %sin the list%n", items.contains("red") ? "": "not "); // display number of elements in the List System.out.printf("Size: %s%n", items.size()); items.remove(1); // remove item at index 1 display(items, "Remove second list element (green):"); // check if a value is in the List System.out.printf("\"red\" is %sin the list%n", items.contains("red") ? "": "not "); // display number of elements in the List System.out.printf("Size: %s%n", items.size()); } // display the ArrayList's elements on the console public static void display(ArrayList items, String header) { System.out.print(header); // display header// display each element in items for (String item : items) System.out.printf(" %s", item); System.out.println(); }

}
Console：
"red" is in the list
Size: 2
Remove second list element (green): yellow
"red" is not in the list
Size: 1