Java List 3种遍历方法详解

你的名字 2023-09-23 22:05 64阅读 0赞

# 1.String For-Each 或者for循环遍历 #

Mango
    Banana
    Apple
    Strawberry

# 2.把List变为array进行遍历 #

public class Test {
        
        public static void main(String[] args) {
        
            List<String> fruitList = new ArrayList<>();
            fruitList.add("Mango");
            fruitList.add("Banana");
            fruitList.add("Apple");
            fruitList.add("Strawberry");
            //2 把List变为array进行遍历String[] 转成Array数组
            String[] array = fruitList.toArray(new String[fruitList.size()]);
            for (int i = 0; i < array.length; i++) {
        
                System.out.println(array[i]);
    
            }     
        }
    }

Mango
    Banana
    Apple
    Strawberry

# 3.使用迭代器进行相关遍历 #

public class Test {
        
        public static void main(String[] args) {
        
            List<String> fruitList = new ArrayList<>();
            fruitList.add("Mango");
            fruitList.add("Banana");
            fruitList.add("Apple");
            fruitList.add("Strawberry");
            //3.使用迭代器进行相关遍历
            Iterator<String> iterator = fruitList.iterator();
            while (iterator.hasNext())//判断下一个元素之后有值
            {
        
                System.out.println(iterator.next());
            }
    
        }
    }

Mango
    Banana
    Apple
    Strawberry

# 代码比较 #

public class Test {
        
        public static void main(String[] args) {
        
            List<String> fruitList = new ArrayList<>();
            fruitList.add("Mango");
            fruitList.add("Banana");
            fruitList.add("Apple");
            fruitList.add("Strawberry");
    
            //1 String For-Each 或者for循环遍历
            for(String str: fruitList){
        
                System.out.println(str);
            }
            System.out.println("===================");
            //2 把List变为array进行遍历String[] 转成Array数组
            String[] array = fruitList.toArray(new String[fruitList.size()]);
            for (int i = 0; i < array.length; i++) {
        
                System.out.println(array[i]);
    
            }
            System.out.println("====================");
    
            //3.使用迭代器进行相关遍历
            Iterator<String> iterator = fruitList.iterator();
            while (iterator.hasNext())//判断下一个元素之后有值
            {
        
                System.out.println(iterator.next());
            }
    
        }
    }

Mango
    Banana
    Apple
    Strawberry
    ===================
    Mango
    Banana
    Apple
    Strawberry
    ====================
    Mango
    Banana
    Apple
    Strawberry