for(元素类型T 每次循环元素的名称O : 循环对象){
//对O进行操作
}
一、常见使用方式。
二、局限性。
foreach虽然能遍历数组或者集合,但是只能用来遍历,无法在遍历的过程中对数组或者集合进行修改,而for循环可以在遍历的过程中对源数组或者集合进行修改。
/** * 描述: * Created by ascend on 2016/7/8. */ public class Client { public static void main(String[] args) { String[] names = {"beibei", "jingjing"}; for (String name : names) { name = "huanhuan"; } //foreach System.out.println("foreach:"+Arrays.toString(names)); //for for (int i = 0; i < names.length; i++) { names[i] = "huanhuan"; } System.out.println("for:"+Arrays.toString(names)); } } 输出: foreach:[beibei, jingjing] for:[huanhuan, huanhuan]
/** * 描述: * Created by ascend on 2016/7/8. */ public class Client { public static void main(String[] args) { List<String> names = new ArrayList<String>(); names.add("beibei"); names.add("jingjing"); //foreach for(String name:names){ name = "huanhuan"; } System.out.println(Arrays.toString(names.toArray())); //for for (int i = 0; i < names.size(); i++) { names.set(i,"huanhuan"); } System.out.println(Arrays.toString(names.toArray())); } } 输出: [beibei, jingjing] [huanhuan, huanhuan]
特别注意的地方!!
原创:http://www.cnblogs.com/adeng/p/5681713.html