Howto Create Map of Vector From Sorted Data

Question

Dear all,

I have the following data as input (sorted by first column):

foo 1 2
foo 3 3
bar 10 11

I want to create a Map of Vector with first column as key of the map such that we have:

foo = {1,2,3,3}
bar = {10,11}

But why my code below doesn't work as expected?

    #include <vector>
    #include <map>
    #include <iostream>
    #include <fstream>
    #include <sstream>

    using namespace std;

    int main  ( int arg_count, char *arg_vec[] ) {
        if (arg_count !=2 ) {
            cerr << "expected one argument" << endl;
            return EXIT_FAILURE;      
        }

        string line;         
        ifstream acemblyfile (arg_vec[1]); 

        map <string, vector<int> > myMapOfVec; 
        vector <string> myVec;  
        string KEY = "" ;    


        if (acemblyfile.is_open())
        {
            while (getline(acemblyfile,line) )
            {
                stringstream ss(line);    
                string KEY_TEMP;
                int VAL1;
                int VAL2;           

                ss >> KEY_TEMP >> VAL1 >> VAL2;

                MyVec.push_back(VAL1);   
                MyVec.push_back(VAL2);   


                if (KEY_TEMP != KEY) {     
                  myMapOfVec[KEY] = MyVec;
                  KEY = KEY_TEMP;            
                  MyVec.clear();          
                }

            }
            acemblyfile.close();      
        }
        else {
            cout << "Unable to open file"; 
        }


for( map<string, vector<int> >::iterator iter = myMapOfVec.begin(); iter != myMapOfVec.end(); ++iter ) {
       vector <int> tempVec = (*iter).second;
       string Key = (*iter).first;
       for (unsigned i =0; i<tempVec.size(); i++) {
          cout << Key << " " << tempVec[i] << endl;
       }
    }

        return 0;
    }

Answer 1

Don't add check for KEY_TEMP != KEY. Because in your case they are equal as foo goes two times one by one. Just

myMapOfVec[KEY].push_back( VAL1 );
myMapOfVec[KEY].push_back( VAL2 );

Answer 2

As Mykola said, you should use the vector in the map instead of creating one yourself. I changed your whole code so it works for me. Note that you wrote some of the variable names with wrong case (MyMapOfVec instead of myMapOfVec) and this led to compiler errors.

Also be sure you don't have a newline at the end of your input file because this will result in repeating the last line.

#include <vector>
#include <map>
#include <iostream>
#include <fstream>
#include <sstream>

using namespace std;

int main  ( int arg_count, char *arg_vec[] ) {
    if (arg_count !=2 ) {
        cerr << "expected one argument" << endl;
        return EXIT_FAILURE;      
    }

    string line;         
    ifstream acemblyfile (arg_vec[1]); 

    map <string, vector<int> > myMapOfVec; 
    string KEY;    


    if (acemblyfile.is_open())
    {
        while (getline(acemblyfile, line) )
        {
            stringstream ss(line);    
            int VAL1;
            int VAL2;

            ss >> KEY >> VAL1 >> VAL2;

            myMapOfVec[KEY].push_back(VAL1);
            myMapOfVec[KEY].push_back(VAL2);

        }
        acemblyfile.close();      
    }
    else {
        cout << "Unable to open file"; 
    }


for( map<string, vector<int> >::iterator iter = myMapOfVec.begin(); iter != myMapOfVec.end(); ++iter ) {
   vector<int> tempVec = (*iter).second;
   string Key = (*iter).first;
   cout << Key;
   for (unsigned i = 0; i < tempVec.size(); i++) {
      cout << " " << tempVec[i];
   }
   cout << endl;
}

    return 0;
}

For your example, this gives the output

bar 10 11
foo 1 2 3 3