CODEWITHSUNDEEP
c++stdvectorstdmap
codepro123
codepro123

Reputation: 81

vector<map<string,MyObject> list inserting data in C++

I have two vector<map<string,MyObject>> type data and I want to move or copy some of MyObject data to copy another in the same type in C++ like below:

using namespace std;

struct MyObject{
  string id;
  string name;
  string phone;
  string salary;
};

//Somewhere else have below type.
vector<map<string,MyObject>> v1;
vector<map<string,MyObject>> v2;

How can I perform the above-given operation?

Upvotes: 0

Views: 97

Answers (2)

Louis Go
Louis Go

Reputation: 2578

A simple example, I change type to std::vector<Myobject> instead of your complext vector of map.

#include <iostream>
#include <string>
#include <vector>

int main()
{
    using std::string;
    using std::vector;

    struct MyObject {
        string id;
        string name;
        string phone;
        string salary;

        MyObject copyidname() {
            MyObject obj{ id, name, "","" };
            return obj;
        }
    };
    // Simplifiled type to demonstrate copy
    vector<MyObject> v1;
    v1.push_back( MyObject{ "1","1","1","1" });
    vector<MyObject> v2;

    // Set capacity to prevent reallocation.
    v2.reserve(v1.size());
    for (auto it = v1.begin(); it != v1.end(); ++it) {
        v2.push_back(it->copyidname());
    }
}

Upvotes: 1

Const
Const

Reputation: 1356

Since you have not provide any constructor to MyObject, compiler will generate necessary move-copy constructors for you.

So no worries, just do

v2 = v1;

for copy

v2 = std::move(v1);

for move

For the conditional copy you can use std::copy_if algorithum from <algorithm> header.

For the conditional move (move_if) you can modify the above algorithm like shown in this post :

template <class InputIt, class OutputIt, class UnaryPredicate>
OutputIt move_if(InputIt first, InputIt last, OutputIt d_first, UnaryPredicate pred)
{
    return std::copy_if(std::make_move_iterator(first), std::make_move_iterator(last),
        d_first, pred);
}

Upvotes: 0

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