向量将CSV列数据添加到向量行中，同时将CSV文件的数据传输到c ++向量中

Question

I am trying to add CSV file into a 2D array vector ie: vector of vector. The following program works well but there is a small problem,

For example to add the following CSV data:

1.4,23.44,24.4,3.0
2.3,4.3,44.5,6.6
3.4,33.2,5.4,3.65

i have used the following code:

void Table::addTableData(string filename)
    vector<vector<float> > vec;

        ifstream file(filename.c_str());


            bool first = false;
            if (file)
            {
                string line;

                while (getline(file,line)) //reading the data line by line
                {
                    istringstream split(line);
                    float value;
                    int col = 0;
                    char sep;

                while (split >> value) //
                {
                    if(!first)
                    {
                        // Each new value read on line 1 should create a new inner vector
                        vec.push_back(std::vector<float>());
                    }

                    vec[col].push_back(value);
                    ++col;

                    // read past the separator
                    split>>sep;
                }

                // Finished reading line 1 and creating as many inner
                // vectors as required
                first = true;
            }

However, The above code executes and adds data into the vector, but rather than adding each value in the first line in inner vector it adds the column as a row in the inner vector. I mean to say the rows and column in the CSV file becomes column and rows in the vector respectively. If I do a cout then I get the following result

1.4 2.3 3.4
23.44 4.3 33.2
24.4 44.5 5.4 
3.0 6.6 3.65   

Therefore. the row and column is reversed, How do I turn things around.

Thank you for looking at this probelm.

Answer 1

Just add each row into a vector, and then push it back, instead of adding to each vector each time:

while (getline(file,line)) //reading the data line by line
{
    std::vector<float> nextRow;

    // etc.
    while (split >> value)
    {
        nextRow.push_back(value);
        split >> sep;
    }

    vec.push_back(nextRow);
}

Answer 2

void Table::addTableData(string filename)

{ vector > vec;

ifstream file(filename.c_str());

bool first = false;
if (file)
{
    string line;
    int col = 0;
    while (getline(file,line)) //reading the data line by line
    {
        istringstream split(line);
        float value;

        char sep;
        vec.push_back(std::vector<float>());
        while (split >> value) //
        {
            /*
            if(!first)
            {
                // Each new value read on line 1 should create a new inner vector
                vec.push_back(std::vector<float>());
            }
            */

            vec[col].push_back(value);

            /* ++col; */

            // read past the separator
            split>>sep;
        }

        // Finished reading line 1 and creating as many inner
        // vectors as required
        /* first = true; */
        ++col;
    }
}

}

this code may work well