Java中List集合遍历的六种方式

た入场券 2023-06-25 04:36 4阅读 0赞

public static void main(String[] args) {
            List<String> list = new ArrayList<>();
            list.add("A");
            list.add("B");
            list.add("C");
    
            /**
             * 第一种：下标遍历
             */
            System.out.println("============1-下标遍历==================");
            for(int i = 0 ; i < list.size() ; i++){
                System.out.println(i +" = "+list.get(i));
            }
    
            /**
             * 第二种：forEach遍历
             */
            System.out.println("===========2-forEach遍历================");
            int count = 0;
            for (String s : list) {
                count ++;
                System.out.println(count + " = "+ s);
            }
    
            /**
             * 第三种：iterator迭代器遍历
             */
            System.out.println("==========3-Iterator迭代器遍历============");
            Iterator<String> iterator = list.iterator();
            int counter= 0;
            while(iterator.hasNext()){
                counter ++;
                System.out.println(counter +" =counter= " + iterator.next());
            }
    
            /**
             * 第四种：jdk8的Lambda的表达式遍历(不需要下标)
             */
            System.out.println("=========4-jdk8的Lambda的表达式(不需要下标)===========");
            list.forEach(str ->{
                System.out.println(str);
            });
    
            /**
             * 第五种：jdk8的Lambda表达式遍历-(使用Stream.iterate获取下标)
             */
            System.out.println("========5-jdk8的Lambda表达式-(使用Stream.iterate获取下标)===========");
            Stream.iterate(0,i -> i + 1 ).limit(list.size()).forEach(i -> {
                System.out.println(i + " =Stream.iterate= " + list.get(i));
            });
    
            /**
             * 第六种：jdk8的Lambda表达式遍历-(使用IntStream.range获取下标)
             */
            System.out.println("=========6-jdk8的Lambda表达式-(使用IntStream.range获取下标)===========");
            IntStream.range(0,list.size()).forEach(i ->{
                System.out.println(i + " =IntStream.range= " + list.get(i));
            });
        }

控制台输出：

============1-下标遍历==================
    0 = A
    1 = B
    2 = C
    ===========2-forEach遍历================
    1 = A
    2 = B
    3 = C
    ==========3-Iterator迭代器遍历============
    1 =counter= A
    2 =counter= B
    3 =counter= C
    =========4-jdk8的Lambda的表达式(不需要下标)===========
    A
    B
    C
    ========5-jdk8的Lambda表达式-(使用Stream.iterate获取下标)===========
    0 =Stream.iterate= A
    1 =Stream.iterate= B
    2 =Stream.iterate= C
    =========6-jdk8的Lambda表达式-(使用IntStream.range获取下标)===========
    0 =IntStream.range= A
    1 =IntStream.range= B
    2 =IntStream.range= C