将STL映射打印为表格

这里有一个使用C++11的可能实现(这里我希望所有向量都有相同的大小(：

#include <map>
#include <string>
#include <vector>
#include <iostream>
void print(std::map<std::string, std::vector<double>> const& m)
{
    // Do nothing for an empty table...
    if (m.begin() == m.end()) { return; }
    for (size_t i = 0; i <= m.begin()->second.size(); i++)
    {
        for (auto const& p : m)
        {
            if (i == 0) { std::cout << p.first << " "; }
            else { std::cout << p.second[i - 1] << " "; }
        }
        std::cout << std::endl;
    }
}
int main()
{
    std::map<std::string, std::vector<double>> m = {
        { "a", { 1, 2, 3, 0 } },
        { "b", { 2, 4, 6, 1 } },
        { "c", { 9, 2, 3, 2 } }
    };
    print(m);
}

这是一个活生生的例子。

灵活适用于任意列和可变长度

void print(const map<string, vector<double>> &m)
{
    size_t rows = 0;
    for (auto const &i : m)
    {
        cout << i.first << ' ';
        if (i.second.size() > rows)
            rows = i.second.size();
    }
    cout << endl;
    for (size_t r = 0; r < rows; ++r)
    {
        for (auto const &i : m)
            if (r < i.second.size())
                cout << i.second[r] << " ";
            else
                cout << "  ";
        cout << endl;
    }
}
int main()
{ 
    map<string, vector<double> > m = {
        { "a", { 1, 2, 3}},
        { "b", { 1, 2, 3, 4}},
        { "c", { 1, 2}},
        { "d", { 1}},
        { "e", { 1, 2, 3, 4, 5, 6, 7}}
    };
    print(m);
}

输出

 a b c d e
 1 1 1 1 1
 2 2 2   2
 3 3     3
   4     4
         5
         6
         7

实时源代码。

这适用于不同长度的矢量：

#include <iostream>
#include <map>
#include <vector>
#include <string>
using namespace std;
int main()
{
    map<string,vector<double> > hashes;
    double arr[]={1,2,3};
    double arr2[]={1,2,3,4};
    hashes.insert(pair<string,vector<double> >("a",vector<double>(arr,arr+sizeof(arr)/sizeof(double))));
    hashes.insert(pair<string,vector<double> >("b",vector<double>(arr,arr+sizeof(arr)/sizeof(double))));
    hashes.insert(pair<string,vector<double> >("c",vector<double>(arr2,arr2+sizeof(arr2)/sizeof(double))));
    for(auto i: hashes)
    {
        cout<< i.first << ' ';
    }
    cout << endl;
    int max_len=0;
    for(auto i: hashes)
    {
    if(i.second.size()>max_len) max_len=i.second.size();
    }
    for(int h=0; h<max_len; h++)
    {
    for(auto i: hashes)
    {
        if(h>=i.second.size()) cout << "  ";
        else cout << i.second[h] << " ";
    }
    cout << endl;
}
return 0;
}

输出：

a b c
1 1 1
2 2 2
3 3 3
    4

#include <iostream>
#include <map>
#include <string>
#include <vector>
using namespace std;
int main()
{
    map<string, vector<double> > m;
    vector<double> a, b, c;
    for (int i = 0; i < 4; ++i) a.push_back(i);
    for (int i = 0; i < 6; ++i) b.push_back(i);
    for (int i = 0; i < 7; ++i) c.push_back(i);
    m["a"] = a;
    m["b"] = b;
    m["c"] = c;
    int n = max(max(a.size(), b.size()), c.size());
    for (map<string, vector<double> >::iterator i = m.begin(); i != m.end(); ++i)
        cout << i->first << ',';
    cout << endl;
    for (int i = 0; i < n; ++i) {
       for (map<string, vector<double> >::iterator it = m.begin(); it != m.end(); ++it)
           cout << (i < it->second.size() ? it->second[i] : 0) << ',';
       cout << endl;
    }
}

我相信有更好的方法来进行迭代并处理尾随的,。

此解决方案适用于任意数量的列，每个列具有任意数量的行。

列名也具有任意长度。

#include <map>
#include <string>
#include <vector>
#include <iostream>
void print(std::map<std::string, std::vector<double>> const& m)
{
    std::vector<size_t> columnWidths;
    std::vector< std::vector<std::string>> columns;
    size_t totalRows = 0;
    // Store all table elements, and the required width of each column
    for ( auto a : m )
    {
       std::vector<std::string> column;
       size_t width = a.first.length();
       column.push_back( a.first );
       size_t rows = 1;
       for ( auto v : a.second )
       {
          ++rows;
          std::string entry = std::to_string(v);
          width = std::max( width, entry.length() );
          column.push_back( entry );
       }
       columnWidths.push_back( width );
       columns.push_back( column );
       totalRows = std::max( totalRows, rows );
    }
    // Print all table elements
    for ( size_t row = 0; row != totalRows; ++row )
    {
        for ( size_t col = 0; col != columns.size(); ++col )
        {
            std::string entry;
            if ( columns[col].size() > row )
            {
                entry = columns[col][row];
            }
            entry.resize( columnWidths[col], ' ' );
            std::cout << entry << ' ';
        }
        std::cout << 'n';
    }
}
int main()
{
    std::map<std::string, std::vector<double>> m =
    {
        { "a", { 1, 2, 3} },
        { "a really really long string", { 1, 2, 3} },
        { "b", { 1, 2, 3, 4, 5 } }
    };
    print(m);
}