python：没有存储数学测验数据

Question

我的任务是为小学生做一个测验。小测验的效果很好。但是我必须计算孩子花了多长时间，并将他们的“username”、“correctAnswers”和“timeTaken”存储到一个.txt文件中，用于孩子所在的特定类。为了做到这一点，我问孩子他们的班级编号，并将他们的信息存储到专门为该班级设计的文件中。 我的问题是：

即使我的代码中有timeTaken=round（etime），时间也不会被舍入

未定义原始输入（我不知道如何定义它）

即使输入了有效的类号，也会出现消息“抱歉，我们无法保存您的数据，因为您输入的类无效。”。在

我到处找遍了，但没找到。任何帮助都将不胜感激。在

import time
import random
import math

def test():
    num1=random.randint(1, 10)
    num2=random.randint(1, num1)

    ops = ['+','-','*']
    operation = random.choice(ops)

    num3=int(eval(str(num1) + operation + str(num2)))

    print ("What is {} {} {}?".format(num1, operation, num2))
    userAnswer= int(input("Your answer:"))
    if userAnswer != num3:
        print ("Incorrect. The right answer is {}".format(num3))
        return False
    else:
        print("correct")
        return True

username=input("What is your name?")
print ("Welcome {} to the Arithmetic quiz".format(username))
usersClass = input("Which class are you in? (1,2 or 3)")
raw_input("Press Enter to Start...")
start = time.time()
correctAnswers=0
for question_number in range(10):
    if test():
        correctAnswers +=1

print("{}: You got {} answers correct".format(username, correctAnswers))
end = time.time()
etime = end - start
timeTaken = round(etime)
print ("You completed the quiz in {} seconds".format(timeTaken))
if usersClass == 1:
    with open("class1.txt","a+") as f:
        f.write("{}:Scored {} in {} seconds".format(username,correctAnswers,timeTaken))

elif usersClass == 2:
    with open("class2.txt","a+") as f:
        f.write("{}:Scored {} in {} seconds".format(username,correctAnswers,timeTaken))

elif usersClass == 3:
    with open("class3.txt","a+") as f:
        f.write("{}:Scored {} in {} seconds".format(username,correctAnswers,timeTaken))
else:
    print("Sorry, we can not save your data as the class you entered is not valid.")

Answer 1

^{}的返回值是一个str对象：

>>> usersClass = input("Which class are you in? (1,2 or 3)")
Which class are you in? (1,2 or 3)3
>>> type(usersClass)
<class 'str'>

因此，您对int对象的后续检查将计算为False（即，'3' != 3），从而得到您所看到的结果。在

比较用户选择的usersClass的条件需要比较同一类型以确保相等。这意味着您可以将返回值input转换为int，并继续将usersClass与{}进行比较，这将满足编写代码时的比较要求

^{pr2}$

或者更改条件，将usersClass与1、2和{}的str表示进行比较。在

if usersClass == '1':
with open("class1.txt","a+") as f:
    f.write("{}:Scored {} in {} seconds".format(username,correctAnswers,timeTaken))
...

至于使用python3的raw_input时遇到的问题，它已被重命名为input：（取自What's New in Python 3.0）

PEP 3111: raw_input() was renamed to input(). That is, the new input() function reads a line from sys.stdin and returns it with the trailing newline stripped. It raises EOFError if the input is terminated prematurely. To get the old behavior of input(), use eval(input()).