python - 尝试从一个子例程获取另一个子例程的列表

Question

我正在从文件中的数据创建一个列表，但我无法在其原始子例程之外使用该列表，我怎样才能将其设为全局，以便我可以在任何我想要的地方使用它并更改它？

def selecting_qs():
    global main_list
    dif = difficulty.get()
    print(main_list,dif)


#main list order:
#Question ID  ,  Difficulty  ,  Topic  ,  Answer ID  ,  Picture ID  ,  Frequency 
def main_file_info():
    main_file = open("main_file.txt","r")
    main_file_info=main_file.readlines()
    for line in main_file_info:
        main_list=line.split("@")

    main_list=main_list[1:len(main_list)-1]
    main_file.close()

    return(main_list)

Answer 1

要传递函数中使用的变量，您只需返回它们，分配它们，然后......传递它们。在您当前的脚本中，这将如下所示:

def selecting_qs(a_list):
    # global  <-- main_list this is not needed and can lead to problems!
    dif = difficulty.get()
    print(a_list, dif)


#main list order:
#Question ID  ,  Difficulty  ,  Topic  ,  Answer ID  ,  Picture ID  ,  Frequency 
def main_file_info():
    main_file = open("main_file.txt","r")
    main_file_info=main_file.readlines()
    for line in main_file_info:
        main_list=line.split("@")

    main_list=main_list[1:len(main_list)-1]
    main_file.close()

    return main_list  # returning the item(s) thus making them accessible from the outer scope

my_main_list = main_file_info()  # assigning the item(s) to a variable
selecting_qs(my_main_list)  # passing the item(s) to another function

如果有任何 Unresolved 问题，请告诉我。