c++ - 如何使用 Qt 将两个单列 csv 文件合并为一个多列 csv 文件？

Question

第一个文件，file1.csv

4.001
3.002
3.003
4.004

第二个文件，file2.csv

100.8
102.4
121.9
107.5

我想要我的最终文件final.csv的格式

4.001 100.8
3.002 102.4
3.003 121.9
4.004 107.5

Answer 1

首先，很遗憾，问题作者没有为解决这个常见问题做出任何努力。或者，也许这是他的家庭作业？:)

Qt的做法：

QFile file1("file1.csv");
file1.open(QIODevice::ReadOnly | QIODevice::Text);

QFile file2("file2.csv");
file2.open(QIODevice::ReadOnly | QIODevice::Text);

QFile res("final.csv");
res.open(QIODevice::WriteOnly);

QTextStream stream;
stream.setDevice(&res);

while (file1.atEnd() == false || file2.atEnd() == false)
{
    QByteArray s1 = file1.readLine();
    if (s1.endsWith("\n"))
    {
        s1.chop(1);
    }

    QByteArray s2 = file2.readLine();
    if (s2.endsWith("\n"))
    {
        s2.chop(1);
    }

    stream << s1 << " " << s2 << "\n";
}

file1.close();
file2.close();
res.close();

Answer 2

#include <fstream>
#include <iostream>
#include <string>
#include <algorithm>

std::vector<std::string>
split_string(std::string src, std::string delim) {
  std::vector<std::string> tokens;
  std::string tmp = src;

  size_t i = 0;
  while (i < tmp.length()) {
    int oi = i;
    i = tmp.find(delim, i);
    if(i != std::string::npos) {
      tokens.push_back(tmp.substr(oi, i - oi));
    } else {
      tokens.push_back(tmp.substr(oi));
      break;
    }
    i += delim.length();
  }
  return tokens;
}

int
main(int argc, char* argv[]) {
    std::ifstream file3("file3.csv");
    std::string buf3;
    std::getline(file3, buf3);
    file3.close();

    std::ifstream file2("file2.csv");
    std::string buf2;
    std::getline(file2, buf2);
    file3.close();

    auto vec3 = split_string(buf3, " ");
    auto vec2 = split_string(buf2, " ");
    int size = vec3.size();
    for (int n = 0; n < size; n++) {
        std::cout << vec3[n] << " " << vec2[n];
        if (n < size - 1)
            std::cout << " ";
    }
    return 0;
}

啊，原来的问题已更新... OMG

那么，接下来

#include <fstream>
#include <iostream>
#include <string>
#include <algorithm>

int
main(int argc, char* argv[]) {
    std::ifstream file1("file1.csv");
    std::ifstream file2("file2.csv");
    std::ofstream out("final.csv", std::ios::app);
    std::string buf1;
    std::string buf2;
    while(file1 >> buf1) {
        file2 >> buf2;
        out << buf1 << " " << buf2 << std::endl;
    }
    file1.close();
    file2.close();
    out.close();
}

Answer 3

    std::ifstream file1("file1.csv");
    std::ifstream file2("file2.csv");
    std::ofstream out("final.csv", std::ios::app);
    std::string buf1;
    std::string buf2;
    while(file1 >> buf1) {
        file2 >> buf2;
        out << buf1 << " " << buf2 <<std::endl;
    }
    file1.close();
    file2.close();
    out.close();
    QFile file11("fil.csv");
    file11.open(QIODevice::ReadOnly | QIODevice::Text);

    QFile file22("final.csv");
    file22.open(QIODevice::ReadOnly | QIODevice::Text);

    QFile res("finally.csv");
    res.open(QIODevice::WriteOnly);

    QTextStream stream;
    stream.setDevice(&res);

    while (file11.atEnd() == false && file22.atEnd() == false)
    {
        QByteArray s1 = file11.readLine();
        if (s1.endsWith("\n"))
        {
            s1.chop(1);
        }

        QByteArray s2 = file22.readLine();
        if (s2.endsWith("\n"))
        {
            s2.chop(1);
        }

        stream << s2 << " " << s1 << "\n";
    }

    file11.close();
    file22.close();
    res.close();