Question

问题在于：创建一个Python程序，允许用户输入每个学生所获得的班级名称，教师姓名，每个学生的姓名和字母等级。该计划应计算并显示获得As，Bs，Cs，Ds和Fs的学生人数。程序应将所有输入和输出信息保存到名为ClassNameGrades.txt的文本文件中。

我到目前为止编写的代码如下。我只是在学习，这是非常简陋的，我道歉。下面是输出。我不知道为什么我会弹出2个额外的记录。有人可以向我解释我做错了什么吗？创建文件，输入被写入文件，但在读取期间它会崩溃。

def main():


    student_num = 0
    count = 0
    a_total = 0
    b_total = 0
    c_total = 0
    d_total = 0
    f_total = 0
    student_num = int(input("Enter the number of students you wish to enter 
    grades for: "))
    gradefile = open('gradebook.txt', 'w')
    for count in range(1, student_num + 1):
        class_name = input('Enter class name: ')
        faculty_name = input('Enter faculty name: ')
        student_name = input('Enter student name: ')
        letter_grade = input('Enter letter grade (A, B, C, D, or F) ')
        print()
        if letter_grade.upper() == 'A':
            a_total += 1
        elif letter_grade.upper() == 'B':
            b_total += 1
        elif letter_grade.upper() == 'C':
            c_total += 1
        elif letter_grade.upper() == 'D':
            d_total += 1
        elif letter_grade.upper() == 'F':
            f_total += 1
        else:
            print('Invalid response')
        gradefile.write(class_name + '\n')
        gradefile.write(faculty_name + '\n')
        gradefile.write(student_name + '\n')
        gradefile.write(letter_grade + '\n')

    gradefile.write(str(a_total) + '\n')
    gradefile.write(str(b_total) + '\n')
    gradefile.write(str(c_total) + '\n')
    gradefile.write(str(d_total) + '\n')
    gradefile.write(str(f_total) + '\n')
    gradefile.close()

    gradefile1 = open('gradebook.txt', 'r')

    class_name = gradefile1.readline()
    while class_name != '':
        faculty_name = gradefile1.readline()
        student_name = gradefile1.readline()
        letter_grade = gradefile1.readline()

        class_name = class_name.rstrip('\n')
        faculty_name = faculty_name.rstrip('\n')
        student_name = student_name.rstrip('\n')
        letter_grade = letter_grade.rstrip('\n')

        print('Class name: ', class_name)
        print('Faculty name: ', faculty_name)
        print('Student name: ', student_name)
        print('Letter grade: ', letter_grade.upper())
        print()
        class_name = gradefile1.readline()
    a_total = gradefile1.readline()
    b_total = gradefile1.readline()
    c_total = gradefile1.readline()
    d_total = gradefile1.readline()
    f_total = gradefile1.readline()
    a_total = a_total.rstrip('\n')
    b_total = b_total.rstrip('\n')
    c_total = c_total.rstrip('\n')
    d_total = d_total.rstrip('\n')
    f_total = f_total.rstrip('\n')
    print('Total As: ', a_total)
    print('Total Bs: ', b_total)
    print('Total Cs: ', c_total)
    print('Total Ds: ', d_total)
    print('Total Fs: ', f_total)
    gradefile1.close()
main()

用户输入：

Enter the number of students you wish to enter grades for: 3
Enter class name: bio
Enter faculty name: jones
Enter student name: smith
Enter letter grade (A, B, C, D, or F) A

Enter class name: bio
Enter faculty name: jones
Enter student name: gray
Enter letter grade (A, B, C, D, or F) B

Enter class name: Bio
Enter faculty name: Jones
Enter student name: Thomas
Enter letter grade (A, B, C, D, or F) B

返回输出：

Class name:  bio
Faculty name:  jones
Student name:  smith
Letter grade:  A

Class name:  bio
Faculty name:  jones
Student name:  gray
Letter grade:  B

Class name:  Bio
Faculty name:  Jones
Student name:  Thomas
Letter grade:  B

Class name:  1
Faculty name:  2
Student name:  0
Letter grade:  0

Class name:  0
Faculty name:  
Student name:  
Letter grade:  

Total As:  
Total Bs:  
Total Cs:  
Total Ds:  
Total Fs:  

Process finished with exit code 0

Answer 1

虽然我现在不与我的开发人员在一起，看看你的代码，但我认为问题在于for语句。而不是范围（1，student_num + 1）尝试重写它，所以你改为使用student_num输入值作为迭代量。基于你编写它的方式，我相信正在发生的事情是for循环是因为student_num + 1而错误地计算迭代。如果用户为student_num输入3，那么3应该是指定的唯一迭代量。

Answer 2

当您阅读文件时，您可以在学生数据和总计数据之间找到一个空白行，但您还没有写过。因此，在你整个文件re之前，while class_name != ''并不是假的。

在两者之间添加一个空白行，您的代码将起作用。

[...]
gradefile.write('\n')
gradefile.write(str(a_total) + '\n')

Python成绩簿分配，写作和阅读记录以及字母等级总数无法获得正确的输出

2 个答案: