Java–foreach循环
foreach是Java5新增,在遍历数组,集合的时候有不错的性能.
- foreach的语法格式:
for(元素类型 每次循环的元素名称 : 循环对象){
}
public static void main(String[] args) {
String[] strs = {
"张三","李四","王五"}; for(String names : strs){
System.out.println(names); } }
2.遍历List
public static void main(String[] args) {
List<String> list = new ArrayList<String>(); list.add("张三"); list.add("王五"); list.add("李四"); for(String name : list){
System.out.println(name); } }
public static void main(String[] args) {
String[] strs = {
"张三","李四","王五"}; //foreach for(String names : strs){
names = "改改"; } System.out.println("foreach:"+Arrays.toString(strs)); //for for(int i=0; i<strs.length; i++){
strs[i] = "改改"; } System.out.println("for:"+Arrays.toString(strs));
2.集合
public static void main(String[] args) {
List<String> list = new ArrayList<String>(); list.add("张三"); list.add("王五"); list.add("李四"); for(String name : list){
name = "改改"; } System.out.println("foreach_list:"+Arrays.toString(list.toArray())); for(int i=0; i<list.size(); i++){
list.set(i, "改改"); } System.out.println("for_list:"+Arrays.toString(list.toArray())); }
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