c++ csv data importing problems [duplicate] - c++

Question

This question already has answers here:
How can I read and parse CSV files in C++?
(39 answers)
Closed 5 years ago.
I am a college student and as part of my final project for a c++ class we are assigned to read a csv file that has distance and force data and then find torque from it. The problem that I am running into is how to actually get the data out of the csv file into a workable format. Currently I have been trying to get it into a matrix, to do this though I will need to first determine the size of the csv file as it is supposed to take any size file. This is the format of the data
Case 1,,,,,x_position (m),y_position (m),z_position (m),F_x (N),F_y (N),F_z (N)16.00,5.00,8.00,394.00,-18.00,396.0022.00,26.00,14.00,-324.00,-420.00,429.0028.00,25.00,21.00,73.00,-396.00,-401.006.00,9.00,12.00,-367.00,-137.00,-143.00
Also obviously the different data pieces (distance and forces) need to be put into different vectors or matrices.
This is what I have so far to try to find the number of lines in the file.
ifstream myfile("force_measurements.csv");
if(myfile.is_open()){
string line;
double num=0;
getline(myfile, line);
if(line==""){
cout<<num<<endl;
myfile.close();
}
else{
num++;
}
}
After this works how would you go about putting the data into a matrix? or would a different format be easier? vectors was my other though.

Answer 1

// you need to include the proper headers here
class vec3D:
{
double m_x, m_y, m_z;
public:
void Set(size_t indx, double val)
{
switch(indx)
{
case 0:
m_x = val;
break;
case 1:
m_y = val;
break;
case 2:
m_z = val;
break;
default:
std::cout << "index out of range" << std::endl;
}
}
double magnitude() { return std::sqrt( m_x*m_x + m_y*m_y + m_z*m_y);}
};
int main()
{
std::ifstream my_data_file ( "your_file_here.csv" );
std::vector<std::array<vec3D, 2>> Pos_Forz;
if ( ! my_data_file.is_open())
{
std::cout << "failure to open the file" <<std::endl;
return -1;
}
std::string temp_str;
double arr[6];
std::array<vec3D,2> temp_3Dvec;
while(!my_data_file.eof())
{
for (int i = 0; i<5 ; i++)
{
getline(my_data_file, temp_str, ",");
arr[i] = std::stod(temp_str);
}
getline(my_data_file, temp_str);
arr[5] = std::stod(temp_str);
for(int i = 0; i<2; i++)
{
for (int j=0; j<3; j++)
{
temp_3Dvec[i].set(j, arr[i*3 + j]);
}
}
Pos_Forz.push_back(temp_3Dvec);
}
for(auto e: Pos_Forz)
{
std::cout << " toque = " << (e[0].magnitude() * e[1].magnitude()) <<std::endl;
}
return 0;
}
Fix what need to be fixed, and inspire yourself from this code, also stop asking this kinda of questions here, you need to read the HOW TO of posting

Answer 2

You have multiple questions. Here's something I used for loading items out of a csv. This gets you started, and you can figure out whether further organization of the data is useful. I personally have classes that take a tokenized line and create an instance of themselves with them.
#include <boost/tokenizer.hpp>
typedef vector<string> csvLine;
void aFunction()
{
string line;
vector<csvLine> usedCollection;
ifstream csvFile("myfile.csv", ios::in);
if (!csvFile)
return -1;
while (getline(csvFile, line))
{
vector<string> tokenizedLine;
boost::tokenizer<boost::escaped_list_separator<char> > tk(
line, boost::escaped_list_separator<char>('\\', ',', '\"'));
for (const string& str : tk)
{
tokenizedLine.push_back(str);
}
usedCollection.push_back(tokenizedLine);
}
csvFile.close();
}
And so usedCollection is a collection of csvLines, where each of those is a collection of strings broken up by the separator character.