C ++将参数3列csv文件中的逗号分隔的浮点数转换为3个独立的向量

Question

I have a csv file which is passed from command line and looks something like:

    2.26645, -0.258901, -213.274
    5.45054, 345.333, 73.1871
    7.18079, 25.156, 125.408
    ...

I want to extract these floats into 3 float vectors, one for each column. I have only been able to extract ALL floats in just one vector,

ifstream input_file;
input_file.open(argv[1],ios::out);

string line;
string value;

while(getline(input_file,line)){
    istringstream ss(line);
    while(getline(ss,value,',')){


    }


}

The issue is that as stated before, I want 3 vectors one for each column instead.

Answer 1

The first problem is because you put the file name into the string stream instead of the file contents. Open a proper input file stream to read the data from the file.

---

After you solved the above problem, the second problem could be solved by reading one line at a time from the file and put into an input string stream . Then parse the input from that stream.

That parsing can be done similarly to what you do know skipping over space and the comma. Or you can use std::getline three times to get each value ( std::getline supports custom "field" separators) and then convert the strings to floating point numbers . Put each number in its own vector.