为什么数组中的单元格的值在运行时会生成0？

Question

为什么SchoolData[1][1] (用户名或分数之类的)总是给0？

score=0
Class = 0
for x in range (0,3):  # the number of times I want the user to complete the quiz
    print ("Enter your name")
    name = input()
    print ("what class")
    Class = input()

    print("1. 9+10=")
    answer = input()
    answer = int(answer)

    if answer == 19:
        print("correct")
        score = score + 1
    else:
        print("wrong")

    print("2. 16+40=")
    answer = input()
    answer = int(answer)

    if answer == 56:
        print("correct")
        score = score + 1
    else:
        print("wrong")

    print("3. 5+21=")
    answer = input()
    answer = int(answer)

    if answer == 26:
        print("correct")
        score = score + 1
    else:
        print("wrong")

    print("4. 5-6=")
    answer = input()
    answer = int(answer)

    if answer == -1:
        print("correct")
        score = score + 1
    else:
        print("wrong")

    print("5. 21-9=")
    answer = input()
    answer = int(answer)

    if answer == 12:
        print("correct")
        score = score + 1
    else:
        print("wrong")

SchoolData=[[0 for x in range(3)] for x in range(3)]  #this is the array
SchoolData[x][0]=name  #this is the users name enter code here
SchoolData[x][1]=score  #this is the score obtained by the user
SchoolData[x][2]=Class  #this is the users class number
raise SystemExit

我运行代码并完成了3次测验。我想知道第一个用户的名字，分数和班号。我尝试从数组中的单元格中提取信息。

Answer 1

SchoolData[1][1]提供嵌套列表中第二个列表的第二个元素。

SchoolData=[[0 for x in range(3)] for x in range(3)]会给你输出：[[0,0,0],[0,0,0],[0,0,0]]，我想这不是你想要的。

在不使用对象的情况下，有一种方法可以快速有效地完成你想做的事情(假设你基于对input的使用来使用python 3.X )：

import collections
school_data = []
questions = ['9+10', '16+40', '5+21', '5-6', '21-9']  

QuizData = collections.namedtuple('QuizData', 'name,class_code,score')
for x in range(0, 5):
    name = input('Enter your name: ')
    class_code = input('Enter class: ')
    score = 0
    for question in questions:
        answer = int(input(question+' = '))
        if answer == eval(question):
            print('Correct!')
            score += 1
        else:
            print('Incorrect.')
    q = QuizData(name, class_code, score)
    school_data.append(q)

这个例子在列表(python docs)中使用了命名元组(python docs)。

要查看2班的最高分数，您可以这样做：

highest_scores = sorted([quiz for quiz in school_data if quiz.class_code == '2'], key=lambda q: q.score, reverse=True)

这将返回一个QuizData命名的元组列表，从高到低排序，其中class_code为'2‘。请注意，您已将class_code保存为字符串，而不是整数。

现在，如果你想在事后访问数据，你需要保存它。一种简单的方法是使用csv模块。

import csv
with open('quiz_data.csv', 'wb') as csv_file:
    quiz_writer = csv.writer(csv_file, delimiter=',')
    quiz_writer.writerow(['Name', 'Class_Code', 'Score'])  # header row
    quiz_writer.writerows(school_data)