Question

问题

执行while循环以验证文件扩展名。如果文件扩展名不是.exe或.bat，请再次询问用户输入。我正在寻找一种不使用import endswith break函数的解决方案。

码

format = " "
while file[:-4] != ".bat" and file[:-4] != ".exe":
    format = input("Enter file you like to open: ")
    if format[:-4] == ".bat" or format[:-4] == ".exe":
        callFunction(format)
    else:
        file = input("Enter file you like to open: ")

Answer 1

要关注Asking the user for input until they give a valid response并使用os.path.splitext()提取文件扩展名：

SELECT dbo.RoundUp(350.00/24, 2)

没有import os ALLOWED_EXTENSTIONS = {".bat", ".exe"} while True: filename = input("Enter file you like to open: ") extension = os.path.splitext(filename)[1] if extension in ALLOWED_EXTENSTIONS: break with open(filename) as f: # do smth with f：

break

没有import os ALLOWED_EXTENSTIONS = {".bat", ".exe"} extension = None while extension not in ALLOWED_EXTENSTIONS: filename = input("Enter file you like to open: ") extension = os.path.splitext(filename)[1] with open(filename) as f: # do smth with f且没有任何导入：

break

没有ALLOWED_EXTENSTIONS = (".bat", ".exe") filename = "" while not filename.endswith(ALLOWED_EXTENSTIONS): filename = input("Enter file you like to open: ") with open(filename) as f: # do smth with f且没有任何导入且没有break：

endswith()

Answer 2

您不需要循环

def ask_exe(prompt='Executable file name? '):
    name = input(prompt)
    if name[-4:] in {'.exe', '.bat'}: return name
    return ask_exe(prompt='The name has to end in ".exe" or ".bat", please retry: ')

[没有休息，没有进口，几乎没有代码...]

正如ShadowRanger所述，我的代码使用set表示法进行成员资格测试，对于3.2之前的Python版本来说是次优的。对于使用tuple的这些旧版本，可以避免在每次执行函数时在运行时计算集合。

...
    # for python < 3.2
    if name[-4:] in ('.exe', '.bat'): return name
...

python：检查文件扩展名并提示如果文件扩展名无效则再次输入

2 个答案: