Randomize a pgn file

[PeterO]

Hello,

I have a database with chessproblems in pgn. Ordered by topics.
Do,you know a tool - to randomize the order of of the game in the pgn?

Peter

[phhnguyen]

it is an easy task. Just compile and run a C++ code as below:

Code: Select all

//
//  ShufflePgn
//
//  Created by Nguyen Pham on 24/7/2022.
//

#include <iostream>
#include <fstream>
#include <vector>
#include <random>
#include <algorithm>
#include <iterator>

int main(int argc, const char * argv[])
{
    std::cout << "shuffle games of a pgn file" << std::endl;
        
    std::string inpath, outpath;

    // arguments
    {
        if (argc < 2) {
            std::cerr << "Usage: shufflepgn INFILE OUTFILE" << std::endl;
            return -1;
        }

        inpath = std::string(argv[1]);
        outpath = std::string(argv[2]);
    }

    std::vector<std::string> pgnVec;
    
    // read in
    {
        std::ifstream file(inpath);
        if (!file.is_open()) {
            return -1;
        }
        
        std::string pgn, line;
        auto cnt = 0;
        while (std::getline(file, line)) {
            auto isEvenLine = line.find("[Event") != std::string::npos;
            if (isEvenLine) {
                if (cnt) {
                    pgnVec.push_back(pgn);
                }
                pgn.clear();
                cnt = 0;
            }
            
            pgn += line + "\n";
            if (!line.empty()) {
                cnt++;
            }
        }
        file.close();
        
        if (cnt) {
            pgnVec.push_back(pgn);
        }
    }
    
    if (pgnVec.size() <= 1) {
        std::cerr << "Error: cannot read input file or it has only or under a game" << std::endl;
        return -1;
    }
    
    // shuffle games
    {
        std::random_device rd;
        std::mt19937 g(rd());
     
        std::shuffle(pgnVec.begin(), pgnVec.end(), g);
    }
    
    // write out
    {
        std::ofstream out(outpath);
        
        for(auto && pgn : pgnVec) {
            out << pgn << "\n";
        }
        out.close();
    }

    return 0;
}

Usage:

Code: Select all

shufflepgn INPUTPATH OUTPUTPATH

[pohl4711]

Hello,

I have a database with chessproblems in pgn. Ordered by topics.
Do,you know a tool - to randomize the order of of the game in the pgn?

Peter

Scid
Sort Database, choose random.

[PeterO]

Thank you VERY MUCH!

Peter