％不支持的操作数类型:“字节"和"STR" [英] unsupported operand type(s) for %: 'bytes' and 'str'

问题描述

我在以下行中收到错误:

I receive the error in the following line:

 command = input("please type command.example open 1")
        #call the serial_connection() function
        ser.write(b"%d\r\n"%command)

基本上，我希望由用户编写输入并将其解析为ser.write，而不要求输入并将字符串直接放入ser.write中，例如:

Essentially I want the input written by the user and parse it into ser.write, without asking for the input and directly putting the string into ser.write such as:

ser.write(b'close1\r\n')

工作正常，仅当我尝试将输入结果用作字符串以包含在ser.write中时，才会出现问题

worked fine, the problem only occurred when i try to use the result of the input as a string to include in ser.write

更多代码:

ser = 0

#Initialize Serial Port
def serial_connection():
    COMPORT = int(input("Please enter the port number: "))
    ser = serial.Serial()
    ser.baudrate = 38400 #Suggested rate in Southco documentation, both locks and program must be at same rate
    ser.port = COMPORT - 1 #counter for port name starts at 0

    #check to see if port is open or closed
    if not ser.isOpen():
        print ('The Port %d is open - Will attempt to close lock 1 Stephan: '%COMPORT + ser.portstr)
        #timeout in seconds
        ser.timeout = 10
        ser.open()
        command = input("please type command.example open 1")
        #call the serial_connection() function
        ser.write(b"%d\r\n"%command)

    else:
        print ('The Port %d is **open** Stephan' %COMPORT)

如有任何澄清，请告知.

for any clarification, kindly advise.

推荐答案

也许您可以先尝试解码字节字符串(如果它不是常量字符串，否则就以普通字符串开头)，然后应用格式，然后对其进行编码回来吗?

Maybe you can try decoding byte string first (if its not a constant string, otherwise just start with normal string), then applying the format, and then encoding it back?

此外，您应该使用%s而不是%d，因为您的命令是用户直接输入的字符串.

Also, you should use %s instead of %d because your` command is a direct input from user, which is a string.

例如-

ser.write(("%s\r\n"%command).encode())

如果不传递任何参数，则默认为当前系统默认编码，也可以指定要使用的编码，例如utf-8或ascii等.ser.write(("%s\r\n"%command).encode('utf-8'))或ser.write(("%s\r\n"%command).encode('ascii'))

If you do not pass any arguments , it defaults to current system default encoding, you can also specify an encoding to use such as utf-8 or ascii , etc. Example of that - ser.write(("%s\r\n"%command).encode('utf-8')) or ser.write(("%s\r\n"%command).encode('ascii'))

这篇关于％不支持的操作数类型:“字节"和"STR"的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！