我有一个类MyClass，它包含两个成员变量foo和bar:
class MyClass:
def __init__(self, foo, bar):
self.foo = foo
self.bar = bar
我有这个类的两个实例，每个实例都有相同的foo和bar值:
x = MyClass('foo', 'bar')
y = MyClass('foo', 'bar')
然而，当我比较它们是否相等时，Python返回False:
>>> x == y
False
我如何使python认为这两个对象相等?
当前回答
如果你想逐个属性进行比较，并查看它是否以及在哪里失败，你可以使用下面的列表推导式:
[i for i,j in
zip([getattr(obj_1, attr) for attr in dir(obj_1)],
[getattr(obj_2, attr) for attr in dir(obj_2)])
if not i==j]
这里的额外优势是，当在PyCharm中调试时，您可以压缩一行并在“Evaluate Expression”窗口中输入。
其他回答
根据具体情况，你可以这样做:
>>> vars(x) == vars(y)
True
参见对象字段中的Python字典
类的实例与==比较是非相等的。最好的方法是将cmp函数赋给你的类，它会做这些事情。
如果你想通过内容进行比较你可以使用cmp(obj1,obj2)
在你的例子中，cmp(doc1,doc2)如果它们的内容相同，它将返回-1。
重写对象中的富比较运算符。
class MyClass:
def __lt__(self, other):
# return comparison
def __le__(self, other):
# return comparison
def __eq__(self, other):
# return comparison
def __ne__(self, other):
# return comparison
def __gt__(self, other):
# return comparison
def __ge__(self, other):
# return comparison
是这样的:
def __eq__(self, other):
return self._id == other._id
总结如下:
It's advised to implement __eq__ rather than __cmp__, except if you run python <= 2.0 (__eq__ has been added in 2.1) Don't forget to also implement __ne__ (should be something like return not self.__eq__(other) or return not self == other except very special case) Don`t forget that the operator must be implemented in each custom class you want to compare (see example below). If you want to compare with object that can be None, you must implement it. The interpreter cannot guess it ... (see example below) class B(object): def __init__(self): self.name = "toto" def __eq__(self, other): if other is None: return False return self.name == other.name class A(object): def __init__(self): self.toto = "titi" self.b_inst = B() def __eq__(self, other): if other is None: return False return (self.toto, self.b_inst) == (other.toto, other.b_inst)
在你的类中实现__eq__方法;就像这样:
def __eq__(self, other):
return self.path == other.path and self.title == other.title
编辑:如果你想让你的对象比较相等当且仅当它们有相等的实例字典:
def __eq__(self, other):
return self.__dict__ == other.__dict__
