C编程: How to extract a particular column from an input file and store in an array

Question

我想将输入文件“out”第 6 列的整数值存储在一个数组中，以便我可以对其进行进一步的操作。

以下是我编写的用于将输入文本文件中的值放入数组的代码，但它没有指定第 6 列中的值:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main()
  {
    int len = 0;
    char line[1000];
    char line2[1000];
    char *pch;
    char c[6] = "ATOM ";
    FILE *fp = fopen("1PGB.pdb", "r");
    FILE *op = fopen("out", "w");
    if(fp == NULL || op == NULL)
      {
        fprintf(stderr, "Error opening file.");
        exit(1);
     }
   else 
     {
       while (fgets(line, sizeof(line), fp) != 0)
        {
         if((pch = strstr (line, c))!= 0)
         fprintf(op, "%s\n", line);
        }
    }
 fclose(fp);
 fclose(op);
 FILE *ip = fopen("out", "r");
 int numberArray[500];
 int i;

 for (i = 0; i < 500; i++)
  {
    fscanf(ip, "%1d", &numberArray[i]);
  }

for (i = 0; i < 500; i++)
{
    printf("Number is: %d\n\n", numberArray[i]);
}

 fclose(ip);
}

以下是我的输入文件:

ATOM      1  N   MET A   1      12.969  18.506  30.954  1.00 15.93           N  

ATOM      2  CA  MET A   1      13.935  18.529  29.843  1.00 17.40           C  

ATOM      3  C   MET A   1      13.138  18.692  28.517  1.00 14.65           C  

ATOM      4  O   MET A   1      12.007  18.222  28.397  1.00 13.04           O  

ATOM      5  CB  MET A   1      14.733  17.216  29.882  1.00 20.72           C  

ATOM      6  CG  MET A   1      15.742  16.983  28.738  1.00 23.81           C  

ATOM      7  SD  MET A   1      17.378  17.025  29.359  1.00 28.11           S  

ATOM      8  CE  MET A   1      17.166  16.055  30.819  1.00 27.51           C  

ATOM      9  N   THR A   2      13.719  19.413  27.573  1.00 12.63           N  

ATOM     10  CA  THR A   2      13.088  19.661  26.283  1.00 12.68           C  

ATOM     11  C   THR A   2      13.561  18.631  25.300  1.00 12.02           C  

ATOM     12  O   THR A   2      14.763  18.432  25.121  1.00 13.07           O  

ATOM     13  CB  THR A   2      13.527  20.980  25.667  1.00 14.62           C  

ATOM     14  OG1 THR A   2      13.307  22.020  26.627  1.00 15.31           O  

ATOM     15  CG2 THR A   2      12.704  21.284  24.409  1.00 14.47           C  

ATOM     16  N   TYR A   3      12.574  18.048  24.642  1.00 11.17           N  

我的问题是我需要对此代码进行哪些更改才能仅提取第 6 列并将其放入数组中。提前致谢。

Answer 1

从您之前@BLUEPIXY评论的帖子开始，即C program: Error reading and printing a particular column from a text file

在开头

op=fopen("out.bin","wb");//open a new binary file in write mode 

然后

//fprintf(op, "%d\n", n6); remove this
fwrite(&n6,sizeof(n6),1,op);// replace it by this

最后

fclose(op); // close the output file
op=fopen("out.bin","rb");//reopen it in read mode
fsseek(op,0,SEEK_END);
int len=ftell(op); // get file size in bytes
fsseek(op,0,SEEK_SET);//rewind to 0;

int *arr=malloc(len);//WARNING: error checking omitted
fread(arr,len,1,op); //load all content in array
fclose(fp);

len/=sizeof(int); //len of array 
for(int i=0;i<len;i++)
    printf("%d",arr[i]); //print content

//when done free memory
free(arr);