how to insert vector object into the map using C++

Question

Hello All,

My requirement is to insert vector object into the map. But, when trying to insert vector object into the map getting the below error.

no instance of overloaded function "std::map<_Kty, _Ty, _Pr, _Alloc>::insert [with _Kty=std::wstring, _Ty=std::wstring, _Pr=std::less<std::wstring>, _Alloc=std::allocator<std::pair<const std::wstring, std::wstring>>]" matches the argument list

Could someone help me how to insert vector object into the map?

#include "stdafx.h"
#include <vector>
#include <iostream>
#include <map>
using namespace std;

int main()
{
std::vector<std::wstring> Locations;
std::map<std::wstring, std::wstring> m_params;

m_params.insert({ L"emailType" , L"email" });
m_params.insert({ L"emailLocation" , Locations });   //Here I am getting an error

for (auto itr = m_params.begin(); itr != m_params.end(); ++itr) 
{

}
return 0;
}

Answer 1

std::map<std::wstring, std::wstring> m_params;

This map object is declared to hold strings, not vectors.

For example -

#include <string>
#include <vector>
#include <map>
#include <iterator>
#include <iostream>
using namespace std;


int main()
{
	map<wstring, vector<wstring>> m_params;

	m_params.insert({ L"vec1", {L"one", L"two"} });
	m_params.insert({ L"vec2", {L"three", L"four"} });

	for (auto& i : m_params)
	{
		wcout << L"Key: " << i.first << endl;
		for (auto& e : i.second)
			wcout << L"Vector element: " << e << endl;
	}


	return 0;
}

Answer 2

If you need a map that contains multiple values with the same key, then consider multimap instead of map.

Answer 3

Hello,

if you only want to add the vector to your map, insert each item of the vector.

for (std::vector<std::wstring>::iterator it = Locations.begin(); it != Locations.end(); ++it)
{
  m_params.insert({ L"emailLocation" , *it });
}

Regards, Guido