python如何回到cod的开始

Question

我对Python3相当陌生，但我正在制作一个简单的程序，在这个程序中我可以选择一个学生的班级，并选择根据平均值、最高分数等显示他们的分数。。。我想知道的是如何返回到代码的开头，这样我就可以选择另一个类，并检查另一组信息，例如B类平均分数。我想知道如何才能返回代码的开头。谢谢你的时间我很感激。在

注：我删去了部分代码

import csv
print("1 for Class A\n2 for Class B\n3 for Class C")
choosen=int(input())
class_a = open('class_a.txt')
class_b = open('class_b.txt')
class_c = open('class_c.txt')
if choosen == 1:
    print("1 for for alphabetical orderwith each students highest score\n2 for highest score, highest to lowest\n3 for average score, highest to lowest")
    cho_two=int(input())
    csv_a = csv.reader(class_a)
    a_list = []
    for row in csv_a:
        row[3] = int(row[3])
        row[4] = int(row[4])
        row[5] = int(row[5])
        minimum = min(row[3:5])
        row.append(minimum)
        maximum = max(row[3:5])
        row.append(maximum)
        average = sum(row[3:5])//3
        row.append(average)
        a_list.append(row[0:9])
    if cho_two == 1:
        alphabetical = [[x[0],x[6]] for x in a_list]
        print("\nCLASS A\nEach students highest by alphabetical order \n")
        for alpha_order in sorted(alphabetical):
            print(alpha_order)
            class_a.close()
    elif cho_two == 2:
        print("\nCLASS A\nThe highest score to the lowest \n")
        for high_scr in sorted(highest_score,reverse = True):
            print(high_scr)
            class_a.close()           
    elif cho_two == 3:
        average_score = [[x[8],x[0]] for x in a_list]
        print("\nCLASS A\nThe average score from highest to lowest \n")
        for ave_scr in sorted(average_score,reverse = True):
            print(ave_scr)
            class_a.close()

代码运行示例

^{pr2}$

Answer 1

Python中普遍接受的方法是使用while True:无限期地循环，然后在您想退出循环并结束程序（或继续放在循环外的代码）时只使用break。在

while True:
    # Run code
    if code_should_end:
        break

将if code_should_end替换为要触发结尾的内容，无论是用户输入还是其他内容。它也可以在你的循环中的任何地方，它不需要只是在最后。在