Question

    vector <map<string,string>> dictionary;
    map <string, string> word1;
    map <string, string> word2;

    word1.insert(pair<string, string>("UNREAL","Abc"));
    word2.insert(pair<string, string>("PROPS","Efg"));

    dictionary.push_back(word1);
    dictionary.push_back(word2);

    vector<map<string, string>>::iterator it;
    it = dictionary.begin();

    for( it; it != dictionary.end(); it++)
    {
                cout << it << " " << it << endl; //ERROR
    }

我想显示存储在vector中的数据。请建议我如何显示矢量字典的输出？

Answer 1

// i is each map in your vector
for (auto i : dictionary) {
    // j is each std::pair<string,string> in each map
    for (auto j : i) {
      // these are the two strings in each pair
      j.first; j.second;
  } 
}

这个答案需要c ++ 11，但是现在几乎所有东西都支持。

Answer 2

为了解决您的问题，您应该这样做：

for(it = dictionary.begin(); it != dictionary.end(); it++){
    for(auto it1=it->begin();it1!=it->end();++it1){
        cout << it1->first << " " << it->second << endl; 
    }
}

但是，我觉得设计有问题。在您的情况下，您不需要vector个map ...您需要vector个pair或map。

对的矢量：

std::vector <std::pair<string,string>> dictionary;
dictionary.emplace_back("UNREAL","Abc");
dictionary.emplace_back("PROPS","Efg");
for(auto const& item:dictionary){
    std::cout << item.first << " " << item.second;
}

<强>图：

 std::map<string,string> dictionary;
 dictionary.insert("UNREAL","Abc");//also :  dictionary["UNREAL"]="Abc";
 dictionary.insert("PROPS","Efg");//also :  dictionary["PROPS"]="Efg";
 for(auto const& item:dictionary){
     std::cout << item.first << " " << item.second;
 }

因为地图不仅仅是一对东西，它是一组对（有点不精确）。

Answer 3

vector和map是两个容器，所以你需要两个嵌套循环。在地图上的嵌套循环中，您的迭代器引用std::pairs，因此您使用.first访问密钥，使用.second访问该值：

vector <map<string,string> > dictionary;
map <string, string> word1;
map <string, string> word2;

word1.insert(pair<string, string>("UNREAL","Abc"));
word2.insert(pair<string, string>("PROPS","Efg"));

dictionary.push_back(word1);
dictionary.push_back(word2);

vector<map<string, string> >::iterator it;
for( it = dictionary.begin(); it != dictionary.end(); ++it)
{
    map<string, string>::iterator it;
    for( nested = it.begin(); nested != it.end(); ++nested)
    {
        cout << it->first << " " << it->second << endl; //ERROR
    }
}

如果您使用C ++ 11，则可以使用Range-based for-loops：

缩短时间

vector <map<string,string>> dictionary;
map <string, string> word1;
map <string, string> word2;

word1.insert(pair<string, string>("UNREAL","Abc"));
word2.insert(pair<string, string>("PROPS","Efg"));

dictionary.push_back(word1);
dictionary.push_back(word2);

for(const map<string, string> &outer : dictionary)
{
    for(const pair<string, string> & inner : outer)
    {
        cout << inner.first << " " << inner.second << endl; //ERROR
    }
}

Answer 4

对类似问题here有答案。该代码允许您使用Alamofire.request(urlString, method: .post, parameters: registrationModel.getParentCandidateDictionary(), encoding: JSONEncoding.default) .validate() .responseJSON() { response in switch response.result { case .failure: // handle errors (including `validate` errors) here if let statusCode = response.response?.statusCode { if statusCode == 409 { // handle 409 specific error here, if you want } } case .success(let value): // handle success here print(value) } }运算符使用任何模板参数打印任何 stl容器。

如何使用地图矢量

4 个答案: