python serial data - incoming data according to previous line result -

i receive data serial (pyserial) line line.

is possible put condition each new incoming line according previous line result ? exemple :

data3 == int(incoming_data_serial) + int(data2) 

this current code editing previous answer deleted author. works fine. gives result :

[63, 0] [64, 63] [64, 64] [63, 64] [63, 63] etc... 

which promising. still need know how incorporate operator (substract exemple) between datas. exemple : instead of [64, 63] 1 data of 64 - 63 meaning 1 !

this code :

#!/usr/bin/python  import serial import time  ser = serial.serial('/dev/ttys1', 9600, timeout=0.1)  class _share:  def __init__(self):     self.last_val = [0 in range(2)]  def calculate(self, val):     #prepare data, convert     self.last_data = val     self.last_val = [self.last_data] + self.last_val[:-1]     print((self.last_val))     return self.last_val  share = _share()  def sensors(theimput):      while true:         try:             time.sleep(0.01)             ser.flushinput()             sensor_reception = ser.readline()             sensor_reception_split = sensor_reception.split()             #data_sensor_milli = int(receptionsplit[3])             data_sensor_pho_1 = int(sensor_reception_split[2])             #data_sensor_tem_1 = int(receptionsplit[1])             #data_sensor_hum_1 = int(receptionsplit[0])             return str(share.calculate(data_sensor_pho_1))         except:             pass         time.sleep(0.1)  f = open('da.txt', 'ab')  while 1:     arduino_sensor = sensors('1')     f.write(arduino_sensor)     f.close()     f = open('da.txt', 'ab') 

#ser serial object #data variable u want update  def sensors(last_data):     temp = []     while true:         c = ser.read()         if not c:             time.sleep(0.1)             continue         if c == '\n' or c == '\r':             break         temp.append(c)     temp = ''.join(temp)     print('raw readings:', temp)     new_data = [int(d) d in temp.strip().split())]       data = [a+b a, b in zip(last_data, new_data)]     print('last data: ', last_data)     print('new data:', new_data)     print('current sum:', data)     last_data = [i in new_data]     return data, last_data  last_data = [0] * 4 f = open('da.txt', 'a')  while true:     try:         sensor_data, last_data = sensors(last_data)         #last_data = [i in last_data]   #uncomment if code doesnt work         f.write(sensor_data.__str__() + '\n')     except:         f.close() 

this code assumes want add last received line of sensor data current line of sensor data. not running sum.