Q:

Python convert strings of bytes to byte array

For example given an arbitrary string. Could be chars or just random bytes:
string = '\xf0\x9f\xa4\xb1'

I want to output:
b'\xf0\x9f\xa4\xb1'

This seems so simple, but I could not find an answer anywhere. Of course just typing the b followed by the string will do. But I want to do this runtime, or from a variable containing the strings of byte.
if the given string was AAAA or some known characters I can simply do string.encode('utf-8'), but I am expecting the string of bytes to just be random. Doing that to '\xf0\x9f\xa4\xb1' ( random bytes ) produces unexpected result b'\xc3\xb0\xc2\x9f\xc2\xa4\xc2\xb1'.
There must be a simpler way to do this?
Edit:
I want to convert the string to bytes without using an encoding

A:

I found a working solution
import struct

def convert_string_to_bytes(string):
    bytes = b''
    for i in string:
        bytes += struct.pack("B", ord(i))
    return bytes       

string = '\xf0\x9f\xa4\xb1'
print (convert_string_to_bytes(string)))
output:
b'\xf0\x9f\xa4\xb1'

