Need a way to make my own bytes

[lopgok]

BPO	4588
Nosy	@loewis, @benjaminp

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2008-12-08.04:14:37.892>
created_at = <Date 2008-12-08.03:29:29.786>
labels = ['interpreter-core', 'invalid', 'type-crash']
title = 'Need a way to make my own bytes'
updated_at = <Date 2008-12-08.05:08:18.330>
user = 'https://bugs.python.org/lopgok'

bugs.python.org fields:

activity = <Date 2008-12-08.05:08:18.330>
actor = 'loewis'
assignee = 'none'
closed = True
closed_date = <Date 2008-12-08.04:14:37.892>
closer = 'benjamin.peterson'
components = ['Interpreter Core']
creation = <Date 2008-12-08.03:29:29.786>
creator = 'lopgok'
dependencies = []
files = []
hgrepos = []
issue_num = 4588
keywords = []
message_count = 4.0
messages = ['77286', '77287', '77288', '77289']
nosy_count = 3.0
nosy_names = ['loewis', 'benjamin.peterson', 'lopgok']
pr_nums = []
priority = 'normal'
resolution = 'not a bug'
stage = None
status = 'closed'
superseder = None
type = 'crash'
url = 'https://bugs.python.org/issue4588'
versions = ['Python 3.0']

[lopgok]

I want to make my own data of types bytes in order to write it out.
For example, I want to write out the bytes 0..9

#!/usr/bin/env python3.0
foo = b''
for i in range (0,10):
    foo += i
#sys.stdout.buffer.write(foo)

Here is the error:
Traceback (most recent call last):
  File "./x.py", line 4, in <module>
    foo += i
TypeError: can't concat bytes to int

I cannot find any function to convert the int i into something
that I can append to foo. I tried chr, which produced a string
typeerror. byte() was not defined. There must be a way to convert
an integral value to a bytes type.

[benjaminp]

bytes([some_number]) should do the trick.

[lopgok]

Doesn't work.
#!/usr/bin/env python3.0

import sys
foo = b''

for i in range (0,10):
    foo += bytes(i)

sys.stdout.buffer.write(foo)

produces a binary file of 45 bytes. Here is a hex dump (the '.'
represent unprintable characters):
+000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
+016 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
+032 00 00 00 00 00 00 00 00 00 00 00 00 00 .............

that is 45 bytes of 0.

[loewis]

Please don't use the bug tracker to obtain help, but only to report
bugs. Use python-list@python.org to get help.

In this specific case, also read Benjamin's answer more carefully.