for in循环

最新推荐文章于 2023-11-04 10:58:53 发布

原创最新推荐文章于 2023-11-04 10:58:53 发布 · 394 阅读

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本文详细解析了JavaScript中的for-in循环与Java中的增强for循环的使用方法及应用场景。通过具体代码示例，展示了如何遍历JavaScript对象属性与数组元素，以及Java中数组与集合对象的迭代。适合初学者理解两种语言的循环结构。

JavaScript中的for in 循环
此处x代表person的属性

var person= {name:"zhangsan",age:"20"};
for (x in person){
	alert(x);
	txt=txt + person[x];
}

此处x代表people的下标

var person= [{name:"zhangsan",age:"20"},{name:"lisi",age:"21"}];
for (x in person){
	alert(x);
	txt=txt + person[x];
}

Java中的增强for循环

public class Test {
   public static void main(String args[]){
   	//循环中都是int
      int [] numbers = {10, 20, 30, 40, 50};
      for(int x : numbers ){
         System.out.print( x );
         System.out.print(",");
      }
      System.out.print("\n");
      //循环中都是string
      String [] names ={"James", "Larry", "Tom", "Lacy"};
      for( String name : names ) {
         System.out.print( name );
         System.out.print(",");
      }
   }
}

编译结果

10,20,30,40,50,
James,Larry,Tom,Lacy,

当循环内容为集合对象时

public class Test{
	public static void main(String args[]){
		HashMap<String,String> hashMap = new HashMap<String, String>();
		map.put("01","张三");
		map.put("02","李四");
		map.put("03","王五");
		map.put("04","赵六");
		Set<Map.Entry<String, String>> entrys = map.entrySet();
		for(Map.Entry<String, String> entry  :entrys){
			System.out.println("键："+ entry.getKey()+" 值："+ entry.getValue());
		}
	}