python - 重构python中的if语句

Question

我想和你一起咨询一段代码。我有:

if tuple_type == Operation.START_SERVER:
    dictionary = ServersDictionary()
    dictionary.start(some_param)
elif tuple_type == Operation.STOP_SERVER:
    dictionary = ServersDictionary()
    dictionary.stop(some_param)
(...)
elif tuple_type == Operation.START_APP:
    dictionary = AppsDictionary()
    dictionary.start(some_param)
elif ...
(....)

我有 27 个 if/elif。通常，我会进入 map - 函数调度程序，但在每个 if/elif 之后，我都有两行代码具有相同的 dictionary 引用。你能建议我一些干净的解决方案来替换那些丑陋的结构吗？

创建 27 个类来应用多态性或 27 个函数听起来不太好……你怎么看？

Answer 1

你说得对，映射是正确的选择。使用 getattr从名称访问方法:

mapping = {Operation.START_SERVER: (ServerDictionary, 'start', some_param),
           Operation.STOP_SERVER: (ServerDictionary, 'stop', some_param),
           Operation.START_APP: (AppsDictionary, 'start', some_param)}
...
cls, method, param = mapping[tuple_type]
dictionary = cls()
getattr(dictionary, method)(param)