On Fri, Apr 02, 2021 at 03:35:23PM +0530, Gopi Manohar Tatiraju wrote: > Hello, > > I am exploring some csv parsers. Link > <https://github.com/ben-strasser/fast-cpp-csv-parser> > I went through the basic example: > > # include "csv.h" > > int main(){ > > io::CSVReader<3> in("ram.csv"); > > in.read_header(io::ignore_extra_column, "vendor", "size", "speed"); > > std::string vendor; int size; double speed; > > while(in.read_row(vendor, size, speed)){ > > // do stuff with the data > > } > > } > > > Here you can see that the variables we pass into the function read_row get > assigned the values of the corresponding columns, but what if I have 20 or > 25 columns, declaring so many variables won't make sense. There should be > some C++ syntax to handle cases like this. What is the concept called? > > What if I don't know how many columns are there in my CSV file or what if > there are 100 columns, we should use a vector or an array. Agreed. But...I > don't want to pass 3 variables in the while loop(vendor, size, speed) but > what I want is, pass a single vector or an array and I can unpack the > vector to get those values. > > Any help would be appreciated.
Hey Gopi, I think maybe you've progressed past this point, but if you are still struggling with it you might try checking on that repository. (Wait, I see that you opened https://github.com/ben-strasser/fast-cpp-csv-parser/issues/119.) In your example, the template parameter must be set at compile-time, so to me it seems strange that the fast-csv designer would have chosen to make the number of columns a template parameter. In my view, if there is no workaround that rules this out---we can have arbitrarily-sized CSVs (even thousands of columns!) and we don't want to force the compiler to instantiate `CSVReader<>` for every single number of columns we might encounter... Hope that helps! Ryan -- Ryan Curtin | "I was misinformed." r...@ratml.org | - Rick Blaine _______________________________________________ mlpack mailing list mlpack@lists.mlpack.org http://knife.lugatgt.org/cgi-bin/mailman/listinfo/mlpack