Question

I want to generate bytes sequence containing string length and string content.
For example, for string 'hello' I want to get b'\x05hello'
After some docs reading I’ve wrote a function:

def LenAndStrBytes(strdata):
  return bytearray([len(strdata)&0xFF])+strdata if strdata!=[] else 0

question:
I’m new in python programming and I wonder, which are best python practices to concatenate different types of data like int and something iterable like bytearray
Did I write my function optimally?

Answer 1

Well, just larsmans points out, it depends on your usage. If you can get the result w/ clear code and fulfilling context limitation, it is nice practice which is suitable.

No need for &0xFF, bytearray checks to ensure values between 0 and 255.

>>> strdata = 'hello'
>>> bytearray([len(strdata)]) + strdata if strdata else bytearray()
bytearray(b'\x05hello')

And you could also

import struct
bytearray(struct.pack('B%ds' % len(strdata), len(strdata), strdata))