I have a .bin file(0's and 1's). I want to read 2 bits of information at a time from that file. How do I do it ?

Explanation of the problem :

Suppose I have the binary text as: " 010010001100101011001"

I want to read " 01 " first and then I want to read " 00 " and so on till I read all the data. How do I do it ?

My code:

fileID = fopen("newencryptedmsg.bin");

A = fread(fileID,[1,2],"uint8");

disp(A)

fclose(fileID);

I've written this code but it's giving me the wrong output.

Expeceted Output : 01

Output of my code : 49 48

Can you please help me with this. Thank you.

[OKo]

fileID = fopen("newencryptedmsg.bin");
A = fread(fileID,[1,2],"uint8") == '1';
disp(A)
fclose(fileID);

Your file is ASCII, so you have to compare your data with chars '1'/'0'

[Vaibav Reddy]

I tried your code but It was saying "Comparison between double and string is not supported".

Answer 1

[Atsushi Ueno]

Reproduce the problem:

fileID = fopen('newencryptedmsg.bin','w');
fwrite(fileID,'010010001100101011001');
fclose(fileID);
type newencryptedmsg.bin % It's binary file, but it looks like ASCII file.

010010001100101011001

fileID = fopen("newencryptedmsg.bin");
A = fread(fileID,[1,2],"uint8");
disp(A)

    48    49

fclose(fileID);

Correct the problem:

fileID = fopen('newencryptedmsg.bin','w');
fwrite(fileID,[0 1 0 0 1 0 0 0 1 1 0 0 1 0 1 0 1 1 0 0 1]');
fclose(fileID);
type newencryptedmsg.bin

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fileID = fopen("newencryptedmsg.bin");
A = fread(fileID,[1,2],"uint8");
disp(A)

     0     1

fclose(fileID);
fileID = fopen("newencryptedmsg.bin");
A = fread(fileID,"uint8")' % just remove [1,2]

A = 1×21

0 1 0 0 1 0 0 0 1 1 0 0 1 0 1 0 1 1 0 0 1

fclose(fileID);

[Vaibav Reddy]

I see what you're trying to tell me. But "newencryptedmsg.bin" is the binary file which I'm trying to access the digits from, it's not an empty file, so I guess I should'nt be using fwrite() for it. I basically want to access the digits from that file 2 at a time.

And I've tried your code but the output is kind of wierd. I got the required " 01 ", but I noticed some text looking like this came above " 01". The text

[Vaibav Reddy]

[Vaibav Reddy]

Ok when I'm trying to copy paste the text that was shown, it's not visible here. But what I can say it's some wierd looking text more like an encrypted text.

Answer 2

[Atsushi Ueno]

Read data from binary file - MATLAB fread (mathworks.com)

Thank you. Now I understand what you mean. I will revise my answer.

fileID = fopen('newencryptedmsg.bin','w');
fwrite(fileID,'Z'); % the contents is 0x5A (01011010b)
fclose(fileID);

fileID = fopen("newencryptedmsg.bin");
A = fread(fileID,2,'ubit1=>uint8');
disp(A)

   0
   1

fclose(fileID);