下面的函数是一个更大程序的一部分，它试图允许用户"喜欢"一部电影，并将该值(通过递增)存储在电影文本文件中。奇怪的是，它在第一次迭代中工作正常(将其读取到列表中，更改值，写入文件)，但在第二次迭代中，出现了错误。
该文件名为"films.txt"，内容为：
0,Genre,Title,Rating,Likes
1,Sci-Fi,Out of the Silent Planet,PG,0
2,Sci-Fi,Solaris,PG,0
3,Sci-Fi,Star Trek,PG,0
4,Sci-Fi,Cosmos,PG,0
5,Drama,The English Patient,15,1
6,Drama,Benhur,PG,0
7,Drama,The Pursuit of Happiness,12,0
8,Drama,The Thin Red Line,18,0
9,Romance,When Harry met Sally,12,0
10,Romance,You've got mail,12,0
11,Romance,Last Tango in Paris,18,0
12,Romance,Casablanca,12,0
此特定功能的代码如下：注意：idnumber指的是每部电影的idnumber。例如，《星际迷航》的ID号是3。
def likeafilm(x,username):
#prompt the user to enter the ID number they require
idnumber=int(input("To confirm, please enter the number of the film you wish to like:"))
#create a list which stores and displays all the data in the films txt file
with open("films.txt",mode="r", encoding="utf8") as f:
allfilms=[]
reader=csv.reader(f)
for row in reader:
allfilms.append([element.strip() for element in row])
#print(allfilms)
print("print the third film", allfilms[3])
print("print the second film", allfilms[2])
print("print the current film selected", allfilms[idnumber])
print("print the like for current film", allfilms[idnumber][4])
allfilms[idnumber][4]=str(int(allfilms[3][4])+1) #this succesfully increments the record in the runtime list by 1
print(allfilms) #this confirms the update - this now needs to be written to file.
with open("films.txt","w") as f:
writer=csv.writer(f)
writer.writerows(allfilms)
print("******BACK TO VIEWING FILMS SELECTION***********")
watchfilms(username)
在第一次迭代，或者我第一次运行程序时，它运行得很好！1是递增的(对于点赞)，一切都很好。第二次出现的错误如下。。。。
print("print the like for current film", allfilms[idnumber][4])
IndexError: list index out of range
更新代码
def likeafilm(x,username):
#prompt the user to enter the ID number they require
idnumber=int(input("To confirm, please enter the number of the film you wish to like:"))
#create a list which stores and displays all the data in the films txt file
with open("films.txt",mode="r", encoding="utf8") as f:
allfilms=[]
reader=csv.reader(f)
for row in reader:
allfilms.append([element.strip() for element in row])
#print(allfilms)
print("print the third film", allfilms[3])
print("print the second film", allfilms[2])
print("print the current film selected", allfilms[idnumber])
print("print the like for current film", allfilms[idnumber][4])
allfilms[idnumber][4]=str(int(allfilms[3][4])+1) #this succesfully increments the record in the runtime list by 1
print(allfilms) #this confirms the update - this now needs to be written to file.
with open("films.txt","w") as f:
writer=csv.writer(f)
#writer.writerows(allfilms)
allfilms.append([element.strip() for element in row])
writer.writerows(allfilms)
print("******BACK TO VIEWING FILMS SELECTION***********")
watchfilms(username)
正如Apollo在下面建议的那样，我可以看到发生了什么(错误)，但不知道如何修复。它在第一次迭代中有效，因为文件是正确的(没有空格)。然而，在第二次迭代中，文件已被覆盖，并且它似乎对文件的内容做了一些操作。第二次出现这个错误：
print("print the like for current film", allfilms[idnumber][4])
IndexError: list index out of range
我在《电影5》(顺便说一句，《英国病人》是一部很棒的电影)中尝试过这个，虽然它第一次更新了它，点赞数增加到了"1"，但第二次没有。
我还尝试将文件写入程序更改为"wb"而不是"w"，但也出现了以下错误：
writer.writerows(records)
TypeError: 'str' does not support the buffer interface
您的想法是正确的，但我会将其分解为两个函数，一个用于增加电影般的效果，另一个用于用户交互。此外，您试图在对内置函数open()的调用中指定"encoding"，这不是一个有效的参数。
import csv
films_file = "films.txt"
def like_film(x):
with open(films_file,mode="r") as f:
reader = csv.reader(f)
records = [row for row in reader]
for rec in records:
if int(rec[0]) == x:
rec[-1] = str(int(rec[-1]) + 1)
with open("films.txt","wb") as f:
writer=csv.writer(f)
writer.writerows(records)
def user_like_film(username):
x = int(input("Enter the ID of the film you wish to like: "))
like_film(x)
watchfilms(username)
找到答案：
在Python 2中，文件需要使用"wb"而不是"w"打开，正如您所建议的那样。
然而，我正在使用Python 3。在Python 3中，所需的语法略有不同。需要使用附加参数打开该文件，即：newline=''。
以下示例：
# Python 2
with open('filmsfile.txt', 'wb') as f:
writer = csv.writer(f)
# Python 3
with open('filmsfile.txt', 'w', newline='') as f:
writer = csv.writer(f)