英文:
Why does using iterator() gives me error, I have also imported package?
问题
Iterator itr = m1.iterator();
while(itr.hasNext()){
    Map.Entry m = (Map.Entry)itr.next();
    if(m2.containsKey(m.getKey())){
        System.out.println(m2.containsKey(m.getKey()));
    }
}
Solution.java:34: 错误: 找不到符号
        Iterator itr = m1.iterator();
                     ^
  符号:   方法 iterator()
  位置: 类型为 Map<Character,Integer> 的变量 m1
1 错误
英文:
Iterator itr=m1.iterator();
    while(itr.hasNext()){
        Map.Entry m=(Map.Entry)itr.next();
            if(m2.containsKey(m.getKey())){
                System.out.println(m2.containsKey(m.getKey()));
            }
    }
Solution.java:34: error: cannot find symbol
        Iterator itr=m1.iterator();
                       ^
  symbol:   method iterator()
  location: variable m1 of type Map<Character,Integer>
1 error
答案1
得分: 2
因为 Map 没有 Iterator,但它有 entrySet()(它有一个 iterator())。就像这样,
Iterator<Map.Entry<Character, Integer>> iter = m1.entrySet().iterator();
英文:
Because Map doesn't have an Iterator, it does have an entrySet() (and that has an iterator()). Like,
Iterator<Map.Entry<Character, Integer>> iter = m1.entrySet().iterator();
答案2
得分: 0
Iterator itr=m1.iterator();应改为:
Iterator iter = m1.entrySet().iterator();
英文:
Iterator itr=m1.iterator(); should be this:
Iterator iter = m1.entrySet().iterator()
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