Bytearray conversion, integer is required error on python3

Question

asking for an integer on 0x00 hex position, python3

>>> command = bytearray()
>>> command.extend(chr(0x00))
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: an integer is required

Answer 1

Bytearrays consist of either bytes ( b'\\x00' ) or byte-sized int s ( 0x00 ). The result of chr(0x00) is a unicode string, however.

You can feed bytearray.extend with either a) a bytes string or b) an iterable of byte-sized integers. Both of these represent "sequence of bytes", which a bytearray is. Also, both can be used with hex notation.

command.extend(b'\x00')
command.extend([0x00])

In case you want to add a single integer, you can also use bytearray.append :

command.append(0x00)

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Since a string is an iterable, bytearray.extend tries to append its elements. These are also strings, however. Hence, the error that an integer was expected.