如何阅读更多的CSV文件 [英] how to read more csv file

问题描述

我有一个C ++脚本，可以读取一个csv文件，对其进行解析并写入另一个csv文件中.
当我尝试为一个文件运行该文件时，它的效果很好.但是，当尝试一起读写某些文件时，只会对第一个文件起作用.

Hi,
I have one C++ script that read one csv file, parse that and write in another csv file.
It works great when I try run that for one file. But when try read and write some files together it only do for first file.

#include "StdAfx.h"
#include <iostream>
#include <fstream>
#include <cstdlib>
#include <cstdio>
#include <cstring>
#include <vector>
#include <string>
#include <stdio.h>
#include <iostream>
#include <string>
#include <conio.h>

using namespace std;

typedef vector<string> stringArray;
typedef vector<char[40]> charArray;
stringArray listString; // store each line in the input file
vector<stringArray> data; // store data of the input file


/*
 * readInput is to read the input file name and get data in that file.
 */
void readInput(char *fileName){
  //  printf("****************ReadInput***************\n");
    // get input file name
   // printf("Input file name: ");
    int sum=0;
   // char fileName[256];
  //  cin.getline (fileName,256);

    // read file
    freopen(fileName, "r", stdin);
    string tmp = ""; // a line in the input file
    while(getline(cin, tmp)){

        // add string into vector
        listString.push_back(tmp);
       // cout << listString[listString.size() - 1] << endl;
        sum=sum+1;
        cout<<sum<<endl;
        if(sum>100000)break;
    }
    printf("\n\n");
}

/*
 * parseValues is to extract data in the input file
 */
void parseValues(){
    printf("****************ParseValue***************\n");
    for (int i = 0; i < listString.size(); ++i){
        char tmp[2048];
        strcpy(tmp, listString[i].c_str()); // copy string to char array
        stringArray tmpArray;
        // utilize string token to extract data
        char * pch;
        pch = strtok (tmp,",");
        while (pch != NULL){
            tmpArray.push_back(pch);
          printf ("%s\t",pch);
            // get the next token
            pch = strtok (NULL, ",");
        }
        data.push_back(tmpArray);
        printf("\n");
    }
}

/*
 * parseValues is to write data to the output.csv
 */
void writeOutput(){
    freopen("output1.csv", "w", stdout);

    //freopen("reza.txt", "w", stdout);
    // for each row

    for (int i = 0; i < listString.size(); ++i){
        // for each column

        for (int j = 0; j < data[i].size(); ++j)
        //if(atof(data[i][1].c_str())>1300)
        {

            cout << data[i][j].c_str() << ",";
        }

       cout << "\n";
        }

}

int main(){

    readInput("book2.csv");

    parseValues();
    writeOutput();
   
    readInput("1.csv");
    parseValues();
    writeOutput();

    return 0;
}

请说一下我该如何解决，我的代码也读取第二个文件?
问候，

Please say how I can solve this and my code read second file too?
Regards,

推荐答案

您只需要循环输入文件列表即可.

Hi,

You need just to loop on a input files list.

int main(){

    int x;
    string fileNameArray[3] = {"book1.csv", "book2.csv", "book3.csv"};
    
    for (x = 0; x < 3; x ++) {
       readInput(fileNameArray[i].c_str());

       parseValues();
       writeOutput();

    }   

    return 0;
}

不要忘记更改输出文件名的每个名称，否则将被删除.


我看到了这个问题，您需要关闭文件，然后在写出put函数的末尾进行操作:

Don''t forget to change output file name each name, other wise it would be erased.


I see the problem, you need to close your file ate the end of the write out put functions :

/*
 * parseValues is to write data to the output.csv
 */
void writeOutput(){


    freopen("output1.csv", "w", stdout);
 
    //freopen("reza.txt", "w", stdout);
    // for each row
 
    for (int i = 0; i < listString.size(); ++i){
        // for each column
 
        for (int j = 0; j < data[i].size(); ++j)
        //if(atof(data[i][1].c_str())>1300)
        {
 
            cout << data[i][j].c_str() << ",";
        }
 
       cout << "\n";
        }

 fclose (stdout);
 
}

最好的问候.
EL GAABEB.

Best Regards.
EL GAABEB.

一个简单的循环并清除缓冲区即可解决问题.

谢谢，

Hi,

A Simple loop and clearing the buffers will do the trick.

Thanks,

自从您谈论C ++以来，我认为您应该更有效地使用C ++(请参阅我对问题的评论):

例如

主要功能:

Since you talk about C++, I think you should use C++ more effectively (see my comment to your question):

E.g.

Main function:

int Main()
{
    CReadWriteCsv in1("In1.csv");
    in1.read(1000);
    CReadWriteCsv in2("In2.csv");
    in2.read(1000);

    in1.append("output.csv");
    in2.append("output.csv");

    return 0;
}

和用于处理CSV文件的类:

And the class to process CSV files:

#ifndef CREARWRITECSV_H
#define CREARWRITECSV_H

#include <string>
#include <iostream>
#include <fstream>
#include <sstream>
#include <vector>
using namespace std;

class CReadWriteCsv
{
public:
    CReadWriteCsv(char* infile): m_infile(infile) {}
    void read(int maxRecords)
    {
        ifstream is(m_infile);
        read(is, maxRecords);
    }
    void append(char* outfile)
    {
        ofstream os(outfile, ios_base::app);
        write(os);
    }

private:
    typedef vector<string> CRecord;
    typedef vector<CRecord> CContent;

    string m_infile;
    CContent m_content;

    void read(istream& is, int maxRecords)
    {
        m_content.clear();

        string line;
        while(maxRecords-- > 0 && getline(is, line))
        {
            CRecord record;
            m_content.push_back(readLine(line, record));
        }
    }
    void write(ostream& os)
    {
        for (CContent::iterator it=m_content.begin(); it!=m_content.end(); ++it)
        {
            writeRecord(*it, os);
        }
    }

    CRecord& readLine(const string& line, CRecord& record)
    {
        string field;
        istringstream iss(line, istringstream::in);
        while(getline(iss, field, ',')) record.push_back(field);
        return record;
    }

    void writeRecord(CRecord& record, ostream& os)
    {
        for(CRecord::iterator it=record.begin(); it!=record.end(); ++it)
        {
            if (it!=record.begin()) os << ",";
            os << *it;
        }
        os << "\n";
    }
};

#endif

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