在python中解压缩对象变量
作者:互联网
我在想是否有某种方法可以解压缩对象属性.
通常这样做涉及以下一系列:
self.x = x
self.y = y
... #etc.
但是应该有可能做得更好.
我在想类似的东西:
def __init__(self,x,y,z):
self.(x,y,z) = x,y,z
或者可能:
带x,y,z解包(个体)
甚至功能如下:
def __init__(self,x,y,z):
unpack(self,x,y,z)
有任何想法吗?还是有更多的Python方式来做到这一点?
解决方法:
您可能想要使用namedtuple,它确实可以完成您想要的事情:
官方Python文档中的代码示例:
Point = namedtuple('Point', ['x', 'y'], verbose=True)
上面的代码等效于:
class Point(tuple):
'Point(x, y)'
__slots__ = ()
_fields = ('x', 'y')
def __new__(_cls, x, y):
'Create a new instance of Point(x, y)'
return _tuple.__new__(_cls, (x, y))
@classmethod
def _make(cls, iterable, new=tuple.__new__, len=len):
'Make a new Point object from a sequence or iterable'
result = new(cls, iterable)
if len(result) != 2:
raise TypeError('Expected 2 arguments, got %d' % len(result))
return result
def __repr__(self):
'Return a nicely formatted representation string'
return 'Point(x=%r, y=%r)' % self
def _asdict(self):
'Return a new OrderedDict which maps field names to their values'
return OrderedDict(zip(self._fields, self))
def _replace(_self, **kwds):
'Return a new Point object replacing specified fields with new values'
result = _self._make(map(kwds.pop, ('x', 'y'), _self))
if kwds:
raise ValueError('Got unexpected field names: %r' % kwds.keys())
return result
def __getnewargs__(self):
'Return self as a plain tuple. Used by copy and pickle.'
return tuple(self)
__dict__ = _property(_asdict)
def __getstate__(self):
'Exclude the OrderedDict from pickling'
pass
x = _property(_itemgetter(0), doc='Alias for field number 0')
y = _property(_itemgetter(1), doc='Alias for field number 1')
使用方法如下:
>>> p = Point(11, y=22) # instantiate with positional or keyword arguments
>>> p[0] + p[1] # indexable like the plain tuple (11, 22)
33
>>> x, y = p # unpack like a regular tuple
>>> x, y
(11, 22)
>>> p.x + p.y # fields also accessible by name
33
>>> p # readable __repr__ with a name=value style
Point(x=11, y=22)
值得一提的是,namedtuple只是常规类,您可以创建一个从其继承的类.
标签:iterable-unpacking,variables,python,class 来源: https://codeday.me/bug/20191122/2062008.html