[PYTHON] Export xlsx file in C ++ using libxlsxwriter.

It takes time to write a large amount of data to an xlsx file with Pythond, so I tried using a C ++ library. As a usage, when exporting a large amount of csv or tsv data to xlsx without using Excel. I forgot to compare the speeds, but due to the difference in cloudiness, C ++ was able to export at high speed. I will compare them soon.

In the case of xlsx file, it supports up to 1,048,576 rows and 16384 columns.

libxlsxwriter

A simple xlsx export library for C. It is published in the Github repository.

A wealth of examples are included.

Installation

It can be used without installation. In that case, it is necessary to specify the path.

$ git clone https://github.com/jmcnamara/libxlsxwriter.git
$ cd libxlsxwriter
$ make
$ sudo make install

How to use

Tab-delimited standard input is output in xlsx format to the file specified by the argument, with tabs as cell column delimiters.

Sample code

tsv2xlsx.cpp

#include <fstream>
#include <iostream>
#include <string>
#include <vector>
#include <boost/algorithm/string.hpp>
#include "xlsxwriter.h"

int main(int argc, char **argv) {
  //Argument check
  if (argc < 2){
    std::cerr << "Usage: " << argv[0] << " output_filename.xlsx" << std::endl;
  }

  //Create Excel Workbooks and Worksheets
  lxw_workbook  *workbook  = workbook_new(argv[argc-1]); // argv[argc-1]Is the file name
  lxw_worksheet *worksheet = workbook_add_worksheet(workbook, NULL);

  std::vector<std::string> v_string;
  int row = 0;
  char input_text[51200]; //Standard input buffer(It may be better to receive standard input with string type)
  while (std::cin.getline(input_text, sizeof(input_text))){
    row++;
    //Do not exceed the maximum number of lines.
    if(row == 1000000){
      break;
    }
    //If the input is blank, do not write.
    if(!input_text[0]){
      continue;
    }
    //Separate the inputs with tabs.
    boost::split(v_string, input_text, boost::is_any_of("\t"));

	//1 line output
    for (int col = 0; col < v_string.size(); col++){
      worksheet_write_string(worksheet, row, col, v_string[col].c_str(), NULL);
    }
  }

  workbook_close(workbook);

  return 0;
}

Compile and run

% g++ tsv2xlsx.cpp -o tsv2xlsx -lxlsxwriter
% cat test.tsv | ./tsv2xlsx test.xlsx