Fixing escaped characters python-xbee

[pabloblo85 at gmail.com]

I am using a XBee to receive data from an arduino network.

But they have AP=2 which means escaped characters are used when a 11 or 13 appears (and some more...)

When this occurs, XBee sends 7D and inmediatly XOR operation with char and 0x20.

I am trying to recover the original character in python but I don't know ho to do it.

I tried something like this:

	read = ser.read(4) #Read 4 chars from serial port
	for x in range (0,4):
		if(toHex(read[x]) != '7d'): #toHex converts it to hexadecimal just for checking purposes
			if(x < 3):
				read[x] = logical_xor(read[x+1], 20) #XOR
				for y in range (x+1,3):
					read[y] = read[y+1]					
				read[3] = ser.read()
			else:
				read[x] = logical_xor(ser.read(), 20) #XOR
	
	data = struct.unpack('<f', read)[0]

logical_xor is:

def logical_xor(str1, str2):
    return bool(str1) ^ bool(str2)

I check if 7D character is in the first 3 chars read, I use the next char to convert it, if it is the 4th, I read another one.

But I read in python strings are inmutables and I can't change their value once they have one.

What would you do in this case? I started some days ago with python and I don't know how to solve this kind of things...