以文本形式读取文件的一部分，以二进制形式读取文件的一部分

Question

I have a file done like this

10 NDI 27 2477 6358 4197 -67 0 VVFAˆ ÿÿÿÿ

The last column is binary. I have to read this file, the problem is that I can not read it as a text because in some lines the last columns has a new line character and thus I wouldn't read the entire line. Then I should read it as a binary file, but then how can I retrieve the first and the third column? I tried by reading bytes in this way:

byte[] lines1 = System.IO.File.ReadAllBytes("D:\\dynamic\\ap1_dynamic\\AP_1.txt");

And then convert it into string with

 for (i = 0; i < lines1.Length; i++) {
       Convert.ToString(lines1[i],2);
 }

but then it reads everything as 0 and 1.. I would like to read the first 8 columns as text, while the last one as binary..

I am using Visual Studio 2013, C#.

Answer 1

Reading the file as binary is correct, as you can convert part of the binary data to text. In this context binary means bytes.

Converting the bytes to binary is not what you want to do. In this context binary means text representation in base 2, but you don't want a text representation of the data.

If the lines are fixed length, you can do something like this to read the values:

int lineLen = 70; // correct this with the actual length
int firstPos = 0;
int firstLen = 3; // correct with actual length
int thirdPos = 15; // correct with actual position
int thirdLen = 3; // correct with actual length
int lastPos = 60; // correct with actual position
int lastLen = 10; // correct with actual length

int lines = lines.length / lineLength;
for (int i = 0; i < lines; i++) {
  int first = Int32.Parse(Encoding.UTF8.GetString(i * lineLen + firstPos, firstLen).Trim());
  int third = Int32.Parse(Encoding.UTF8.GetString(i * lineLen + thirdPos, thirdLen).Trim());
  byte[] last = new byte[lastLen];
  Array.Copy(lines1, i * lineLen + lastPos, last, 0, lastLen);
  // do something with the data in first, third and last
}