read text file byte by byte

[census]

Steven D'Aprano wrote:

> On Sat, 12 Dec 2009 10:35:55 +0100, census wrote:
>
>>> I've got some questions -
>>> 1) How do I read the file byte by byte 2) Should I use streams? If so
>>> and I get my entire scrambled text in stream can I just write it to the
>>> binary file?
>>>
>>> Thanks
>>> Dave
>> 
>> f = open ("binaryfile", "r")
>> bytearray = map (ord, f.read () )
>> 
>> Stores the content of binaryfile in the list bytearray.
>
> If it's a binary file, you should open it in binary mode:
>
> f = open ("binaryfile", "rb")
>
>
>

Add the "b" flag to both in and out file if you prefer it:

def scramble (a): return (a + 13) % 256

infile = open ("binin", "rb")
outfile = open ("binout", "wb")

bytearray = map (ord, infile.read () )
scrambled = map (scramble, bytearray)
map (lambda x : outfile.write (chr (x) ), scrambled)

infile.close ()
outfile.flush ()
outfile.close ()