Question

这意味着当用户输入字典中的文件扩展名时，只会突破循环：

def ext_input():
    ext_dict = {'doc', 'docx', 'pdf', 'rtf', 'txt', 'wps', 'csv'}
    while True:
        print('Enter the file extension (.pdf, .txt, etc..) type "help" for a list of extensions')
        fileExt = input()
        if fileExt == "help":
            print(ext_dict)
            return
        elif fileExt != ext_dict:
            print('Please enter a correct file extension (.pdf, .txt, etc..) type "help" for a list of extensions')
        else:
            print("\"%s\" has been selected" % fileExt)
            break

对于python来说还是比较新的，任何指向正确方向的指针都会很棒

Answer 1

首先，您的help_dict不是dict，而是set。

第二：你将一个字符串与一个集合进行比较 - 当然赢得了永远不会比较平等。测试集合是否包含元素是使用in运算符完成的：if something in myset: - 对于非appartenance，您只需使用not in。我想，你想：

elif fileExt not in ext_dict: # XXXX

Answer 2

您的ext_dict应该是一个列表而不是字典（它不是，请参阅Bruno的答案），它允许修改此代码：

def ext_input():
    ext_dict = ['doc', 'docx', 'pdf', 'rtf', 'txt', 'wps', 'csv']
    while True:
        print('Enter the file extension (.pdf, .txt, etc..) type "help" for a list of extensions')
        fileExt = input()
        if fileExt == "help":
            print(ext_dict)
            return
        elif fileExt not in ext_dict:
            print('Please enter a correct file extension (.pdf, .txt, etc..) type "help" for a list of extensions')
        else:
            print("\"%s\" has been selected" % fileExt)
            break

使用字典作为用户输入的答案键

2 个答案: