Question

我正在尝试使用python打开文件。有两个函数，一个用于获取文件名并打开文件，第二个用于检查扩展名是否有效。检查一段时间，3个没有大写字母，数字或特殊字符的字符。

e.g。第一次传递testfile.txt会运行正常。但是如果我再次运行代码并使用test.123之类的变量进行测试然后输入testfile.txt，则进入while循环，但如果我使用test.abc，则响应是正确的。然后如果在错误输入后输入testfile.txt或任何其他正确的文件，代码会将我带回while循环。我在哪里弄错了。

def openfiles():
    """
        this function to accept the file name and open it.

    :rtype : object
    """
    found_file = False
    while not found_file:
        try:
            filename = input("Please provide the name of the file")
            ext_check = checkFileEXT(filename)
            if ext_check is True:
                input_file = open(filename)
            found_file = True
        except IOError:
            print("The requested file was not opened. Either the file name or extension was not correct. \
            Please try again")
    return input_file


def checkFileEXT(filename):
    period = "."
    index = filename.find(period)
    request_file_name = False
    if index == -1:
        request_file_name = True
    else:
        provided_ext = filename[index + 1:len(filename)]
        for char in provided_ext:
            if char not in ("a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "0", "p", "q", "r", "t", "u", "v", "x", "y", "z"):
                request_file_name = True
    while request_file_name is True or len(provided_ext) != 3:
        print("The file name provided was not correct")
        openfiles()
    return True
print(openfiles())

我遇到的另一个问题是断点越过了。它似乎甚至在Debug中运行代码。这将在第二次通过时发生。

Answer 1

这是你的问题：

while request_file_name is True or len(provided_ext) != 3:

无法将request_file_name设置为False或更改provided_ext的长度。因此，循环要么运行要么永远运行。

Answer 2

检查文件的更好方法如下：

new_file = open_file()
while check_file(new_file) is False:
    new_file = open_file()

print(new_file)

这减少了两个函数相互调用的复杂逻辑，并将它们相互分离。您需要对代码进行一些重新分解，因为这只显示了基本逻辑。

为什么这个Python代码在循环中运行

2 个答案: