Question

我生成一个2D矢量，想要检查特定单词在矢量的一行中出现的频率。这是我的矢量示例：

Monkey Monkey Banana
Banana Monkey Monkey
Banana Banana Banana

我想要结果：

First row: Monkey: 2 of 3

Second row: Monkey: 2 of 3

Third row: Banana: 3 of 3

使用我的代码，我不知道如何从2D矢量中获取行。我可以获得代码中显示的列。这是代码：

vector<string> read_file(string filename) {
   string classname;
   vector<string> v_classname;

   ifstream myfile(filename);
   while (myfile >> classname)
       v_classname.push_back(classname);

return v_classname;}


int main(int argc, char* argv[]) { 

    int num;
    vector<vector<string>> class_matrix;
    vector<string> v_classes;


    cout << "Enter number vectors: " << endl;
    cin >> num;

    for (int i = 0; i < num; i++) {
        string name;



        cout << "Enter name of file " << i + 1 << ": ";
        cin >> name;

        v_classes = read_file(name);
        class_matrix.push_back(v_classes);


    }
    for (int i = 0; i < num; i++) {

    unordered_map<string, size_t> m;
    for (const auto& s : class_matrix[i])
        ++m[s];

    for (const auto& p: m)
        cout << i+1 << ". column: " << p.first << "\t" << p.second << " of " << v_classes.size() << endl;
}



return 0;}

Answer 1

很抱歉这么晚。此功能可以帮助您：

void CalcMostFrequentInRow( const std::vector<std::vector<std::string>>& input )
{
    std::vector<std::multimap<size_t, std::string, std::greater<size_t>>> VectorAllData;// Holds elements max_repetitions => key in each row. All data stored here
    for ( auto SubVector : input )
    {
        std::map<std::string, size_t> TempCounterMapByKey; // Holds key => max_repetitions
        std::multimap<size_t, std::string, std::greater<size_t>> TempKeysCounterMapByCount; // For current roe holds max_repetitions => key descending with a help of std::greater

        std::for_each(SubVector.begin(), SubVector.end(), [&TempCounterMapByKey]( const std::string& key )
                      {
                          TempCounterMapByKey[key]++; // Counter of unique key in row
                      });
        std::for_each(TempCounterMapByKey.begin(), TempCounterMapByKey.end(), [&TempKeysCounterMapByCount]( const auto pair )
                      {
                          TempKeysCounterMapByCount.insert(std::make_pair(pair.second, pair.first));
                      });

        VectorAllData.push_back(TempKeysCounterMapByCount); // Save data statistic for each row

    }

    //Trace all data
    size_t RowId = 1;
    const size_t COUNT_ROWS = VectorAllData.size();
    for ( size_t i = 0; i < COUNT_ROWS; i++ )
    {
        auto El = VectorAllData[i];
        std::cout << "Row " << RowId++ << " contains";
        const size_t COUNT_KEYS_IN_ROW = input[i].size();
        if( El.size() > 0 )
        {
            size_t MostFrequentIdCount = El.begin()->first;
            auto range = El.equal_range(MostFrequentIdCount);// Range of most frequent elements
            const size_t CountMostFrequentElements = El.count(MostFrequentIdCount);

            // Specific trace if we have several elements with max counter of most frequent keys
            if ( CountMostFrequentElements > 1 )
            {
                std::cout << " several most frequent elements(" << MostFrequentIdCount << " repetition of " << COUNT_KEYS_IN_ROW <<  ") and their value is: ";
                std::for_each(range.first, range.second, []( const auto El )
                              {
                                  std::cout << El.second << ", ";
                              });
                std::cout << std::endl;
            }
            else // Specific trace if we have one element with max counter of most frequent keys
            {
                std::cout << " one most frequent element(" << MostFrequentIdCount << " repetition of " << COUNT_KEYS_IN_ROW <<  ") and its value is: ";
                std::for_each(range.first, range.second, []( const auto El )
                              {
                                  std::cout << El.second << " ";
                              });
                std::cout << std::endl;
            }
        }
    }
}

各地的代码都有评论，希望一切都是明白的。因此，对于您的计划，您可以致电：

vector<vector<string>> class_matrix;
//...
//Input data
//...
CalcMostFrequentInRow(class_matrix);

一切都应该有效。例如，我将显示我的测试输入数据：

#include <stdio.h>
#include <iostream>
#include <string>
#include <vector>
#include <map>
#include <algorithm>

int main()
{
    std::vector<std::vector<std::string>> InputVector {{"qwe","qwe","rty"}, {"rty","qwe","rty"}, {"asd","asd","asd"}, {"asd","qwe","rty"}};
    CalcMostFrequentInRow(InputVector);

    return 0;
}

输出是：

Row 1 contains one most frequent element(2 repetition of 3) and its value is: qwe 
Row 2 contains one most frequent element(2 repetition of 3) and its value is: rty 
Row 3 contains one most frequent element(3 repetition of 3) and its value is: asd 
Row 4 contains several most frequent elements(1 repetition of 3) and their value is: asd, qwe, rty,

使用无序映射测试2D矢量的行

1 个答案: