It s not clear exactly what you re trying to do.

The way you convert bytes into a string is by calling the .decode method. This gives you bytes:

data = s.recv(64)

And this transforms that into a string:

data = data.decode( utf-8 )

But you re trying to call hex(), which takes a single integer and returns the corresponding hexadecimal value. That doesn t make much sense in the context of your question.

I needed to convert a byte MAC address to a string representing hex values. @birdistheword99 showed me the way...

a MAC address retrieved from the system looks like: b xacgxb27-xcc . This is not very reader friendly. To make it into a string of hex digits...

import binascii

mac_bytes = b xacgxb27-xcc 
mac_str = binascii.hexlify(mac_bytes).decode()
print(mac_str)

Yields...

ac67b2372dcc

Have you tried import struct?

new = struct.unpack( =i , data)

So what you have is a bytes object, and it sounds like what you want is a string containing the hexadecimal representation of those bytes.

The answers to this question describe how to do this in standard Python, but from a quick check with the online MicroPython console you can t just call .hex() on the bytes object itself, and we don t have the binascii or codecs modules, so none of those methods will work.

However it s not difficult to do what you want with plain Python:

>>> data = b hello! 
>>>   .join([ {:02x} .format(b) for b in data])
 68656c6c6f 

Here we re using a list comprehension to get each byte b in turn from the bytes object data. We re then formatting that into a two-character string in hexadecimal format, with a leading zero if necessary, using {:02x} .format(b). The expression inside the square brackets gives us a list of those two-character strings, so finally we join them together separated by an empty string.

If you want a space between each two-digit group, for example, replace the with .

I find this a useful starting point for string formatting methods in Python. MicroPython supports the %-operator and str.format methods, but not formatted string literals.

While I think @larsks answer is the best (calling the .deocde() ), you originally said that you wanted it in hex.

It s worth noting that the ubinascii module is available on most micropython ports and has a hexlify function for converting to hex. It will still return a bytes string though, so you may still need to call .decode() depending on your intended purpose: https://docs.micropython.org/en/latest/library/ubinascii.html

You might also want to look at the builtin from_bytes class method built into the int type. You can use it with:

x = int.from_bytes(byte_string, byte_order)

https://docs.micropython.org/en/latest/library/builtins.html?highlight=to_bytes

Minimal example:

import network
import binascii 
print(binascii.hexlify(network.WLAN(network.STA_IF).config( mac )).decode())