python串口如何读取byte类型数据并访问

#! usr/bin/env pyhton
# coding:utf-8
import serial
import time
import csv
import os
originaltime = 0.0
starttime = 0.0
endtime = 0.0
endtimebefore = 0.0
def savedis(force , csvfile):
    f = open(csvfile, 'a', encoding='utf-8', newline='')  # 'w'覆盖写 'a'追加写
    csv_writer = csv.writer(f)
    global endtime
    time_head = time.strftime("%Y-%m-%d %H:%M:%S", time.localtime(endtime))
    time_sec = (endtime - int(endtime)) * 1000
    timesample = "%s.%03d" % (time_head, time_sec)
    csv_writer.writerow([timesample, str(force)])
    # f.close()
def main():
    # 文件处理
    current_path = os.path.abspath(__file__)[:-len('sbt_test.py')]
    currenttime = time.localtime(time.time())
    csvfile = current_path + str(currenttime.tm_hour) + '-' + str(currenttime.tm_min) +'-'+ str(currenttime.tm_sec) + '.csv'
    f = open(csvfile, 'a', encoding='utf-8', newline='')  # 'w'覆盖写 'a'追加写
    csv_writer = csv.writer(f)
    csv_writer.writerow(['timestamp(ms)', 'display(N)'])
    f.close()
    # 串口声明
    port = 'COM7' #根据设备管理器的端口号更改
    baud = 115200
    timex = 0.02  # 超时设置,None：永远等待操作，0为立即返回请求结果，其他值为等待超时时间(单位为秒)
    global starttime
    global endtime
    global endtimebefore
    sbtforce = serial.Serial(port, baud, timeout=timex) #此行不能放在循环内，因为耗时长
    sendmessage = sbtforce.write(bytes.fromhex('FE010701000001CFFCCCFF'))
    offset = 20  # 收到的数据跟放大器上的示数不对应，需要减去一个偏差值，根据示数调整
    while True:
        endtime = time.time()
        startdata = sbtforce.read(1)
        if startdata == b'\xFE':
            buffer = sbtforce.read(10)
            if (buffer[9] == 255):
                print("buffer=",buffer)
                force = buffer[2:6]
                print('force = ',force)
                force = force[0] << 24 | force[1] << 16 | force[2] << 8 | force[3]
                if force > 100000000:
                    force = force - 2**32 - offset
                if force > 0:
                    force -= offset
                force = force / 100.0
                print('压力值：', force)
                savedis(force, csvfile)
if __name__ == '__main__':
    main()

sbtforce = serial.Serial(port, baud, timeout=timex)

data = sbtforce.read(10)

data[0]

data[0:1]

ser1 = serial.Serial(port='/dev/ttyUSB1', baudrate=115200, bytesize=8, parity='N', stopbits=1)

 s.write(data) #不指明编码方式，直接发送
 s.write(data.encode('utf-8'))  # utf-8 编码发送
 s.write(data.encode('hex'))  # 转成16进制后发送