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Question

I have a simple function to read bytes from serial port.

Simply code looks like

read_bytes = serial.read(5)

After that I print a result and for example I have

b'\\x01\\x02\\x03\\x04\\x05'

There is an option to catch bytes at specific position ? For example If I want to print byte at second position it should print for me b'\\x02' . I read documentation but functions find and index do different stuff.

Answer 1

You can treat the bytes class as an iterable, and you can access its elements as you would with a simple string like:

read_bytes = b'\x01\x02\x03\x04\x05'
read_bytes[2]
# 3
read_bytes[0]
# 1

So just use list indexing to access an element with a specific index.

Update:

In case you want to retrieve the element as a bytes object you can slice it from the sequence:

read_bytes[2:3]
# b'\x03'
read_bytes[0:1]
# b'\x01'

A more verbose way is to get the element and cast it as bytes

bytes([read_bytes[2]])

Note: you have to pass the value in an iterable otherwise bytes will return a sequence of null bytes with a length of the integer value it received.