"NameError: global name 'ser' is not defined" python twitter

Question

我在 Python 中遇到以下问题，但我不知道为什么：

"Traceback (most recent call last):   File
C:/Users/W7-32/Downloads/TW31.py", line 82, in <module>
    driptwit()  ## Llamada a la funcion driptwit   File "C:/Users/W7-32/Downloads/TW31.py", line 71, in driptwit
    ser.write("1") NameError: global name 'ser' is not defined

源代码：

 # lIBRERIAS

 import twitter
 import tweepy
 import serial
 import time
 import threading
 import os
 import datetime

 ##Consumer y Access de Twitter Developers from tweepy import API
 consumer_key = 'QpaLpmQOS0DMTt2hFxy5WN40i'
 consumer_secret = 'WoUssPI9gIdiEIu0LSWG2bvGuAlvF8WTDStdFTkj5OIPwbeLth'
 access_token_key = '935906436-aMBTKoPOZshZhCRRil1vNCTUKPxQBSiuXe181hLp'
 access_token_secret = 'pxYs26cMqxQbhxQtgfIGnUjWGP1eLlK9mVxdaLeorPfZ4'

 #Autenticacion y conexion con Twitter
 #auth = tweepy.OAuthHandler(consumer_key, consumer_secret)
 ##auth.set_access_token(access_token_key, access_token_secret)

 #api = tweepy.api(consumer_key, consumer_secret, access_token_key, >     access_token_secret)
 #api=tweepy.API(auth)
 ##Declaracion del puerto serial

 auth=tweepy.OAuthHandler(consumer_key, consumer_secret)
 auth.set_access_token(access_token_key, access_token_secret)

 api=tweepy.API(auth)


 locations = ['COM3','COM4','COM5','COM6']

 for device in locations:

     try:

         ser = serial.Serial(device, baudrate=9600, bytesize=8,

         parity=serial.PARITY_NONE, stopbits=serial.STOPBITS_ONE)

         print ("\nArduino found on: " + ser.portstr + " please >     wait...\n")
         time.sleep(2)
         break
     except:
                 print "Failed to connect on", device

 ## check serial port
 def checkokay():
     ser.flushInput()
     time.sleep(3)
     line = ser.readline()
     time.sleep(3)
     if line == ' ':
         line = ser.readline()
     print("here")


 print('Bienvenido a Print_Twitter')


 def driptwit():
     status = []
     x = 0
     status = api.user_timeline('FerCMejia')  ##grab latest statuses
     checkit = [s.text for s in status]  ##put status in an array
     drip = checkit[0].split()  ##split first tweet into words

     ## check for match and write to serial if match
     if (drip[0] == '#dripPrint'):
         print("Recibiendo Twitter, Imprimiendo")
         ser.write("1")
     else:
         if drip[0] == '#dripPrintStop':  ##break if done
             ser.write("0")
             print("Impresion detenida, esperando instruccion")
         else:
                 print("Esperando Tweet")
                 ser.write("0")


 while 1:
         driptwit()  ## Llamada a la funcion driptwit
         time.sleep(20)  ## Espera de 20 seg para volver a leer el status

虽然端口连接了Arduino，但它给我一个未定义的错误。

这是 .py 存档：

Archive Python

我使用 Pycharm 和 Python2.7 解释器，Windows7 32 位。

Answer 1

ser 不是全局变量。您在 for 循环内定义它，因此它的范围仅限于该循环。在 for 循环上方执行此操作：

ser = None
for device in locations:

这使得它的范围不仅仅局限于for循环。 for 循环现在将使用在循环中调用它时刚刚定义的那个变量。然后，在函数体中，您需要在顶部添加 global 关键字，以确保当您调用 ser 时它获取全局变量而不是尝试创建新变量。像这样：

def checkokay():
     global ser
     ser.flushInput()

其他功能相同：

def driptwit():
     global ser
     status = []

现在你的变量是全局变量，你的函数正在使用变量的全局版本。

"NameError: global name 'ser' is not defined" python twitter

"NameError: global name 'ser' is not defined" python twitter

python

pyserial