有没有办法避免在初始化类时调用__init__
,比如从类方法中调用?
我试图用Python语言创建一个不区分大小写和标点符号的字符串类,用于有效的比较,但在不调用__init__
的情况下创建一个新实例时遇到了问题。
>>> class String:
def __init__(self, string):
self.__string = tuple(string.split())
self.__simple = tuple(self.__simple())
def __simple(self):
letter = lambda s: ''.join(filter(lambda s: 'a' <= s <= 'z', s))
return filter(bool, map(letter, map(str.lower, self.__string)))
def __eq__(self, other):
assert isinstance(other, String)
return self.__simple == other.__simple
def __getitem__(self, key):
assert isinstance(key, slice)
string = String()
string.__string = self.__string[key]
string.__simple = self.__simple[key]
return string
def __iter__(self):
return iter(self.__string)
>>> String('Hello, world!')[1:]
Traceback (most recent call last):
File "<pyshell#2>", line 1, in <module>
String('Hello, world!')[1:]
File "<pyshell#1>", line 17, in __getitem__
string = String()
TypeError: __init__() takes exactly 2 positional arguments (1 given)
>>>
我应该用什么替换string = String(); string.__string = self.__string[key]; string.__simple = self.__simple[key]
,才能用切片初始化新对象?
编辑:
由于受到以下答案的启发,初始化器已被编辑为快速检查无参数。
def __init__(self, string=None):
if string is None:
self.__string = self.__simple = ()
else:
self.__string = tuple(string.split())
self.__simple = tuple(self.__simple())
https://stackoverflow.com/questions/2168964
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