Question

我仍然忙于我的多项选择测验计划。我快到了。只有几个错误仍然可以解决。该程序会记录您正确，错误和当前百分比的数字问题。但是，我的程序不会运行，因为最初，用户没有回答任何问题。因此，他们有NULL％正确。我的代码如下：

import random
import sys
import os
import math

right_answer_total = float(0)
wrong_answer_total = float(0)
answer_total = float(right_answer_total + wrong_answer_total)
percentage = 100 * (float(right_answer_total) / float(answer_total))

word_drills = {'class': 'Tell Python to make a new kind of thing.',
               'object': 'Two meanings: the most basic kind of thing, and any instance of some thing.',
               'instance': 'What you get when you tell Python to create a class.',
               'def': 'How you define a function inside a class.',
               'self': 'Inside the functions in a class, self is a variable for the instance/object being accessed.',
               'inheritance': 'The concept that one class can inherit traits from another class, much like you and your parents.',
               'composition': 'The concept that a class can be composed of other classes as parts, much like how a car has wheels.',
               'attribute': 'A property classes have that are from composition and are usually variables.',
               'is-a': 'A phrase to say that something inherits from another, as in a Salmon *** Fish',
               'has-a': 'A phrase to say that something is composed of other things or has a trait, as in a Salmon *** mouth.'}


def start():
    # For loop that creates a list named keys. It grabs 3 random keys from the dictionary word_drills
    keys = [x for x in random.sample(word_drills, 3)]
    # User is presented with a question. A value from the previous randomly selected keys is selected as the 'question'
    correctanswer = word_drills[random.choice(keys)]
    print "Question: ", correctanswer 
    # Set the variables key1, key2, & key3 to the 3 keys in the list 'keys'
    key1, key2, key3 = keys[0], keys[1], keys[2]
    # User is presented with 3 choices.
    print "\n\n(a)%s   (b)%s   (c)%s" % (key1, key2, key3)
    a, b, c = word_drills[key1], word_drills[key2], word_drills[key3]
    selection = raw_input("> ")
    print selection
    if selection == "a":
        if a == correctanswer:
            print "That's correct!"
            answered_correctly()
        else:
            print "I'm sorry, that is incorrect..."
            not_answered_correctly()
    elif selection == "b":
        if b == correctanswer:
            print "That's correct!"
            answered_correctly()
        else:
            print "I'm sorry, that is incorrect..."
            not_answered_correctly()
    elif selection == "c":
        if c == correctanswer:
            print "That's correct!"
            answered_correctly()
        else:
            print "I'm sorry, that is incorrect..."
            not_answered_correctly()
    else:
        print "That is not a valid selection."
        exit(0)

def answered_correctly():
    global right_answer_total
    right_answer_total += 1
    stat_tracking()

def not_answered_correctly():
    global wrong_answer_total
    wrong_answer_total += 1
    stat_tracking()

def stat_tracking():
    os.system('cls' if os.name=='nt' else 'clear') 
    print "-" * 37
    print "|         Stat Tracking             |"
    print "-" * 37
    print "| Correct | Incorrect |  Percentage  |"
    print "-" * 37
    print "|    %d    |     %d     |     %d %%     |" % (right_answer_total, wrong_answer_total, percentage) 
    print "-" * 37
    print "\n\n\n"
    start()

stat_tracking()

我不确定是否有针对此的解决方法，或者我可能会解决这个问题。任何和所有的帮助将不胜感激。感谢。

Answer 1

没有回答任何问题时，没有任何意义可以打印出来。添加除数为0的特殊检查，并打印100％，或只打印N / A或其他东西。

此外，以下是您的代码的一些提示。

right_answer_total = float(0)
wrong_answer_total = float(0)
answer_total = float(right_answer_total + wrong_answer_total)
percentage = 100 * (float(right_answer_total) / float(answer_total))

如果您将from __future__ import division放在代码的开头，则所有float都是不必要的。

print "|    %d    |     %d     |     %d %%     |" % (right_answer_total, wrong_answer_total, percentage)

不推荐使用字符串插值运算符。如果不需要Python 2.5兼容性，请使用str.format。

print "|    {}    |     {}     |     {} %     |".format(right_answer_total, wrong_answer_total, percentage)

Answer 2

自启动时，用户尚未回答任何问题，您最初可以将其设置为0。

如果稍后出现问题，您可以事先检查零分割

if answer_total != 0:
    percentage = 100 * (float(right_answer_total) / float(answer_total))
else:
    percentage = 0.0

您也可以考虑使用浮点文字（如0.0）来初始化变量，而不是使用float函数来转换整数。

修复了您可能找到的错误之后，最好使用您的代码转到http://codereview.stackexchange.com以获得一些通用编码建议。

Answer 3

将第9行更改为：

percentage = 100 * (float(right_answer_total) / float(answer_total)) if (right_answer_total>0 and answer_total >0) else 0

Python中的零分区阻止程序运行

3 个答案: