Python Invalid Int（）Error

Question

import turtle 
index = 0 #to traverse through list 
turtle.setup(800,600) # Change the width of the drawing to 800px and the 
height to 600px. 
wn = turtle.Screen() 
sammy = turtle.Turtle() 

inFile = open('mystery.txt','r') 
outFile=inFile.read() 
outFileContent = outFile.split() 
while index != (len(outFileContent)): #for item in the list 
    if str(outFileContent [index]) == "UP": #if the current index goes up, pen up 
     sammy.penup() 

    elif str(outFileContent [index]) == "DOWN": #else if its down, pen down 
     sammy.pendown() 

    elif outFileContent[index].isalpha() == False : #if its a number, go to 
those coordinates 
     sammy.goto (int(outFileContent[index]),int(outFileContent[index+1])) #convert from str to int 

    index+=1 #goes to next value in list 


    print ((int(outFileContent [index]), int(outFileContent[index+1]))) #make sure its printing the right coordinates 

inFile.close() 
wn.mainloop() 

所以这个程序应该打开一个列表，然后让乌龟在列表上执行命令。如果这条线读起来，那么乌龟把笔放起来。如果该行读取向下，则乌龟放下笔。如果这条线是一对数字，那么乌龟会进入这些坐标。以下是文件“mystery.txt”的内容：

UP 
-218 185 
DOWN 

然而，当我运行程序，它输出：

Traceback (most recent call last): 
File "C:\Users\Yariel\Google 
Drive\Coding\Python\Scripts\Files\turtle_file_mystery_shape.py", line 23, in <module> 
print ((int(outFileContent [index]), int(outFileContent[index+1]))) #make 
sure its printing the right coordinates 
ValueError: invalid literal for int() with base 10: 'DOWN' 

我不知道为什么它调低到一个整数，我从未指定。 （如果您查看print语句中的坐标，则会输出正确的坐标）。 那么有什么帮助？关于如何解决这个问题？

Answer 1

坐标是一个特殊的输入案例。您需要将index增加1以容纳第二个int。

# ... 
elif outFileContent[index].isalpha() == False : #if its a number, go to those coordinates 
    sammy.goto (int(outFileContent[index]),int(outFileContent[index+1])) #convert from str to int 
    # move print to here; indexing changed 
    print ((int(outFileContent [index]), int(outFileContent[index+1]))) 
    # additional increment to index to accommodate second int 
    index += 1 

index+=1 #goes to next value in list 
# ... 

Answer 2

我强烈建议学习如何使用ipdb。从字面上看，只需将import ipdb; ipdb.set_trace()一行放在打印语句之前，然后继续执行n并继续执行c。

 22  import ipdb; ipdb.set_trace() 
---> 23  print ((int(outFileContent [index]), int(outFileContent[index+1]))) #make sure its printing the right coordinates 
    24 

ipdb> outFileContent 
['UP', '-218', '185', 'DOWN'] 
ipdb> outFileContent[index] 
'-218' 
ipdb> outFileContent[index+1] 
'185' 
ipdb> c 
(-218, 185) 

    21 
---> 22  import ipdb; ipdb.set_trace() 
    23  print ((int(outFileContent [index]), int(outFileContent[index+1]))) #make sure its printing the right coordinates 

ipdb> outFileContent[index] 
'185' 
ipdb> outFileContent[index+1] 
'DOWN' 

很明显，您的错误来自您的while循环的第二个循环后，您将索引增加一。我假设你想增加三个指数？

请注意，您可能必须执行pip install ipdb --user。

Answer 3

而不是修补你的代码，我建议你重新考虑它。以下过程中的返工由线一次的神秘文件中的行，而不是所有的，是希望您更轻松地增加和调试：

import sys 
from turtle import Turtle, Screen 

screen = Screen() 
# Set width of the drawing to 800px and height to 600px 
screen.setup(800, 600) 

sammy = Turtle() 

commands = {'UP': sammy.penup, 'DOWN': sammy.pendown} 

with open('mystery.txt') as inFile: 

    for line in inFile: 
     content = line.rstrip().split() 

     if len(content) == 1 and content[0] in commands: 

      commands[content[0]]() # eg. UP and DOWN 

     elif len(content) == 2 and not content[0].isalpha() and not content[1].isalpha(): 

      # seem to be numbers, convert from str to int and go to those coordinates 
      sammy.goto(int(content[0]), int(content[1])) 

     else: 
      print("Invalid input:", content, file=sys.stderr) 

screen.mainloop()