對 set 的遍歷
一般是迭代遍歷:
Set<String> set = new HashSet<String>(); Iterator<String> it = set.iterator(); while (it.hasNext()) { String str = it.next(); System.out.println(str); }
for循環遍歷:
for (String str : set) { System.out.println(str); }
是不是簡單些?
優點還體現在泛型 假如 set中存放的是Object
Set<Object> set = new HashSet<Object>();
for循環遍歷:
for (Object obj: set) { if(obj instanceof Integer){ int aa= (Integer)obj; }else if(obj instanceof String){ String aa = (String)obj } ........ }