writing numbers in binary file

[eskandari]

On May 31, 12:30 pm, MRAB <pyt... at mrabarnett.plus.com> wrote:
> eskandari wrote:
> > Hi,
> > I am a newbie in python. I have an data.pickle file which is
> > serialized form of an "array of strings", I want to write their
> > offsets in another binary file, so an C++ program can read and analyse
> > them.
> > But when I try to write offset (number) in binary file, it raise
> > exception below in line  "offsetfile.write(offset)"
> > "TypeError: argument 1 must be string or read-only buffer, not int"
>
> > I search the internet, find that all suggest converting number to
> > string ---with str()---and then write string to file.
> > But I shouldn't do this. because the above mentioned C++ function,
> > read file with this assumption that there are numbers in file.
> > So I want to know, Is there any way to produce an binary file
> > containing numbers same as the way C++ does?
> > Can anybody help me?
>
> You can't write ints to a file, but you can write bytestrings ('str' in
> Python 2, 'bytes' in Python 3).
>
> Use the 'struct' module to convert the int to a bytestring, and remember
> to open the file as a binary file.

Thanks alot,
I have an question, if I do so, Will the second program (C++ program)
which process this file, encounter any problem while parsing the file?
It find number of integers by filelen/4 and ..... (It assumes that
file was created as the same way which C++ does)
Thanks in advance