Question

The first row of my data file is the headers for the three (or four) columns of data:

%b02_a08    b02_a08_counts  b02_a08_eu

As you can see, the columns are TAB delimited. When I use getline(), it mashes the whole line together. If I use getline(,,'\t'), it returns %b02_a08 for the line. I need the line separated out, because I read each header.

If anyone knows of a way to read the headers from a data file and put them into a vector<string> so that I can run Regex on them to find the one with “eu” in it, that is all I need to do. Well, that and read the columns of data, which I will probably run into the same TAB delimited problem, there.

Answer 1

Use the stream Luke…

as in,

// process the header
std::getline(some_input_stream, line))
{
  std::istringstream str(line);
  // Now reaad each field
  str >> header_1 >> header_2 >> header_3;
  if (str >> header_4)
  {
    // process the optional column
    have_col_4 = true;
  }
}

// Now to read the rows
while(some_input_stream >> col_1 >> col_2 >> col_3)
{
  if (have_col_4)
    some_input_stream >> col_4;
}

The last block can be done with std::getline too (i.e. read a line, construct a stream, then read from the stream), however this tends to be somewhat slower…