Irritating bytearray behavior

Mon Sep 16 22:09:35 EDT 2019

On 16Sep2019 20:37, Ian Pilcher <arequipeno at gmail.com> wrote:
> msg[4:] = ip.packed
> sock.sendto(msg, dest)
>>This doesn't work in the IPv4 case, because the bytearray gets truncated
>to only 8 bytes (4 bytes plus the size of ip.packed).
>>Is there a way to avoid this behavior copy the contents of ip.packed
>into the bytearray without changing its size?

Sure:
 msg[4:4+len(ip.packed)] = ip.packed
What you did was ask to replace all the bytes from 4 onward. What you 
should do is replace just the correct bytes.
Cheers,
Cameron Simpson <cs at cskk.id.au>