Writing 8-bit bytes

General Usage
1

I wanted to create a certain file consisting of 8-bit bytes (to conform with a picture format).

In the following, the value of Q was always in the range 0-255. But the command
write(OUT, convert(UInt8,floor(Q)))
actually wrote zero-padded 16-bit bytes to the file OUT. Thus output file came out twice the size I expected. Indeed, using another programming language, I got the desired result by “dealing” 8-bit bytes (like card) between to two files (the other of which got filled with 0’s and thus subsequently discarded).

How can I write 8-bit bytes in Julia? I’m using Windows 10 on a 64-bit machine, if that makes a difference.

Thank you.

2

It works fine for me. For example:

julia> a = rand(1024);

julia> open("tst.dat", "w") do f
           for x in a
               write(f, convert(UInt8, floor(x)))
           end
       end

julia> filesize("tst.dat")
1024
3

Either “weird.”
Or…perhaps filesize is counting 16-bit blocks?
That would be consistent. I’ll try filesize with my code and see what it reports.

4

filesize returns the size in bytes (8 bits).

Probably you have some mistake, but it is hard to tell what is going on if you don’t provide a self-contained example like what I posted.

5

Agreed.
I can reproduce your example. I’ll look for my mistake now.

6

Found it. Thanks… Probably this topic should be deleted.