将信息添加到文本文件，TypeError：'_io.TextIOWrapper'对象不可下标

Question

Basically I'm trying to make it so that it saves a test score that you got too a text file that also contains your username and password and will continue to add to this file when you complete quizes, but i keep getting at the line after it states something like "You got 40% and got a D"

Traceback (most recent call last):
    File "N:\Y10 Python\course work onbe.py", line 141, in <module>
    listy=usernamelist[line]
    TypeError: '_io.TextIOWrapper' object is not subscriptable

The part of the code with the error is:

found=False
while found==False:
    usernamelist=open("username.txt","r")
    for line in usernamelist.readlines():
        if (username in line):
            found=True
            listy=usernamelist[line]
            usernamelist.close()
    if found==True:
        usernamelist = open("username.txt","a")
        listy=listy.rstrip(["\n"])
        usernamelist.write(","+topic+"-"+difficulty+"-"+grade+"\n")
        usernamelist.close()
    else:
        print ("Invalid username")

My whole code is:

import os
import sys
#Login-in function

nuser=input("Do you already have an account?(Y/N)")
nuser=nuser.lower()
found=False
if nuser==("y"):
    while found==False:
        username=input("Enter username:")
        password=input("Enter password:")
        usernamelist=open("username.txt","r")
        for line in usernamelist:
            if (username+","+password in line):
                found=True
        if found==True:
            print ("Welcome "+username)
        else:
            print ("Invalid username or password, try again")
        usernamelist.close()
#Creating an account    
if nuser==("n"):
    name=input("Enter name:")
    name=name[:3]
    age=input("Enter age:")
    username=name+age
    print ("Your username is "+username)
    password=input("Enter a password:")
    usernamelist = open("username.txt","a")
    usernamelist.write(username+","+password+"\n")
    print ("Your account has been created, welcome "+username)
    usernamelist.close()

#Option selection
optionchosen=False
option=input("What do you want to do? Take a quiz(a), see a report on all your quizzes(b)or a report on a specific topic(c)?") 
option=option.lower()
#Topics and questions
if option==("a"):
    optionchosen=True
    topicchosen=False
    difficultychosen=False
    while topicchosen==False:
        topicchosen=True
        while difficultychosen==False:
                difficultychosen=True
                topic=input("What topic do you want to be quizzed on?History, Music or Computing")
                topic=topic.lower()
                difficulty = input("What difficulty do you want, easy, medium or hard?")
                difficulty=difficulty.lower()
                if topic == ("history"):
                    topicchoseen=True
                    if difficulty == ("easy"):
                        difficultychosen=True
                        scriptpath = "history_easy.py"
                        import history_easy
                        from history_easy import score
                    elif difficulty == ("medium"):
                        difficultychosen=True
                        scriptpath = "history_medium.py"
                        import history_medium
                        from history_medium import score
                    elif difficulty == ("hard"):
                        difficultychosen=True
                        scriptpath = "history_hard.py"
                        import history_hard
                        from history_hard import score
                    else:
                        print ("Invalid difficulty")
                        difficultychosen=False
                elif topic == ("music"):
                    topicchoseen=True
                    if difficulty == ("easy"):
                        difficultychosen=True
                        scriptpath = "music_easy.py"
                        import music_easy
                        from music_easy import score
                    elif difficulty == ("medium"):
                        difficultychosen=True
                        scriptpath = "music_medium.py"
                        import music_medium
                        from music_medium import score
                    elif difficulty == ("hard"):
                        difficultychosen=True
                        scriptpath = "music_hard.py"
                        import music_hard
                        from music_hard import score
                    else:
                        print ("Invalid difficulty")
                        difficultychosen=False
                elif topic == ("computing"):
                    topicchoseen=True
                    if difficulty == ("easy"):
                        difficultychosen=True
                        scriptpath = "computing_easy.py"
                        import computing_easy
                        from computing_easy import score
                    elif difficulty == ("medium"):
                        difficultychosen=True
                        scriptpath = "computing_medium.py"
                        import computing_medium
                        from computing_medium import score
                    elif difficulty == ("hard"):
                        difficultychosen=True
                        scriptpath = "computing_hard.py"
                        import computing_hard
                        from computing_hard import score
                    else:
                        print ("Invalid difficulty")
                        difficultychosen=False
                else:
                    print("Invalid topic")
                    topicchoseen=False
    print (score)


    if score==(5):
        grade=("A")
        print ("You got 100% and got a "+grade)
    elif score==(4):
        grade=("B")
        print ("You got 80% and got a "+grade)
    elif score==(3):
        grade=("C")
        print ("You got 60% and got a "+grade)
    elif score==(2):
        grade=("D")
        print ("You got 40% and got a "+grade)
    elif score==(1):
        grade=("E")
        print ("You got 20% and got a "+grade)
    else:
        grade=("F")
        print ("You got 0% so got a "+grade)
    found=False
    while found==False:
        usernamelist=open("username.txt","r")
        for line in usernamelist.readlines():
            if (username in line):
                found=True
                listy=usernamelist[line]
                usernamelist.close()
        if found==True:
            usernamelist = open("username.txt","a")
            listy=listy.rstrip(["\n"])
            usernamelist.write(","+topic+"-"+difficulty+"-"+grade+"\n")
            usernamelist.close()
        else:
            print ("Invalid username")



#Report 1
if option==("b"):
    optionchosen=True
    person=input("Whats the username of the person you want to produce a report for?")
    found=False
    while found==False:
        usernamelist=open("username.txt","r")
        for line in usernamelist:
            if (person in line):
                found=True
                print (line)
        if found==True:
            break   
        else:
            print ("Invalid username or password, try again")
            usernamelist.close()

Answer 1

usernamelist is a file handle that you opened with usernamelist=open("username.txt","r") , and you are treating it as a dict/list with listy=usernamelist[line] , which causes the said error.

Reading the rest of your code it's apparent that you want listy to simply be the line that matches the username, so it will work if you replace the line listy=usernamelist[line] with listy=line .