Writing a stream of bytes

[BartC]

On 15/01/2016 15:55, jmp wrote:
> Hi pyple !
>
>
> I'd like to write a stream of bytes into a file. I'd like to use the
> struct (instead of bytearray) module because I will have to write more
> than bytes.
>
> let's say I want a file with 4 bytes in that order:
>
> 01 02 03 04
>
> None of these work:
>
> import struct
>
> with open('toto', 'wb') as f: f.write(struct.pack('4B', *[1,2,3,4]))
> with open('toto', 'wb') as f: f.write(struct.pack('<4B', *[1,2,3,4]))
> with open('toto', 'wb') as f: f.write(struct.pack('>4B', *[1,2,3,4]))
>
> I always end up with the following bytes on file:
> !hexdump toto
> 0000000 0201 0403

Why is the hex dump doing 16-bits at a time? Get a byte dump, then it 
might actually be the right output.

Anyway, this seems to work:

data=bytearray([1,2,3,4])

f = open("output", "wb")
f.write(data)
f.close()

Doubtless there are plenty of other ways.

-- 
Bartc