跟踪python中的实例 [英] Keep track of instances in python
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问题描述
在程序结束时,我想将一个类的所有实例中的特定变量加载到字典中。
例如:
class Foo():
__init __(self):
x = {}
foo1 = Foo()
foo2 = Foo()
foo ...等。假设实例的数量会有所不同,我想要每个Foo()实例的x dict,加载到一个新的dict。
我在SO中看到的例子假定已经有实例列表。
类A(对象):
instances = []
def __init __(self,foo):
self.foo = foo
A.instances.append )
在程序结束时,您可以创建如下的字典:
foo_vars = {id(instance):instance.foo例如在A.instances中}
pre>
只有一个列表:
> > a = A(1)
>>>> b = A(2)
>>>> A.instances
[< __ main __。一个对象在0x1004d44d0>,< __ main __。一个对象在0x1004d4510>]
>>> id(A.instances)
4299683456
>>>> id(a.instances)
4299683456
>>>> id(b.instances)
4299683456
Toward the end of a program I'm looking to load a specific variable from all the instances of a class into a dictionary.
For example:
class Foo():
__init__(self):
x = {}
foo1 = Foo()
foo2 = Foo()
foo...etc.
Let's say the number of instances will vary and I want the x dict from each instance of Foo() loaded into a new dict. How would I do that?
The examples I've seen in SO assume one already has the list of instances.
解决方案 One way to keep track of instances is with a class variable:
class A(object):
instances = []
def __init__(self, foo):
self.foo = foo
A.instances.append(self)
At the end of the program, you can create your dict like this:
foo_vars = {id(instance): instance.foo for instance in A.instances}
There is only one list:
>>> a = A(1)
>>> b = A(2)
>>> A.instances
[<__main__.A object at 0x1004d44d0>, <__main__.A object at 0x1004d4510>]
>>> id(A.instances)
4299683456
>>> id(a.instances)
4299683456
>>> id(b.instances)
4299683456
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