AttributeError：无法在python中设置属性
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AttributeError: can't set attribute in python
提问by Pratyush Dhanuka
Here is my code
这是我的代码
N = namedtuple("N", ['ind', 'set', 'v'])
def solve()
items=[]
stack=[]
R = set(range(0,8))
for i in range(0,8):
items.append(N(i,R,8))
stack.append(N(0,R-set(range(0,1)),i))
while(len(stack)>0):
node = stack.pop()
print node
print items[node.ind]
items[node.ind].v = node.v
In the last line I cant set the items[node.ind].vvalue to node.vas I want, and am getting the error
在最后一行中，我无法将items[node.ind].v值设置node.v为我想要的，并且出现错误
"AttributeError: can't set attribute"
I don't know what's wrong but it must be something based on syntax as using statements like node.v+=1is also showing same error. I'm new to Python, so please suggest a way to make the above change possible.
我不知道出了什么问题，但它必须基于语法，因为 using 语句node.v+=1也显示相同的错误。我是 Python 新手，所以请提出一种方法来使上述更改成为可能。
采纳答案by Ignacio Vazquez-Abrams
items[node.ind] = items[node.ind]._replace(v=node.v)
(Note: Don't be discouraged to use this solution because of the leading underscore in the function _replace. Specifically for namedtuple some functions have leading underscore which is not for indicating they are meant to be "private")
（注意：不要因为函数 _replace 中的前导下划线而气馁使用此解决方案。特别是对于namedtuple，一些函数有前导下划线，这并不是为了表明它们是“私有的”）
回答by jonrsharpe
namedtuples are immutable, just like standard tuples. You have two choices:
namedtuples 是不可变的，就像标准元组一样。你有两个选择：
- Use a different data structure, e.g. a class (or just a dictionary); or
- Instead of updating the structure, replace it.
- 使用不同的数据结构，例如一个类（或只是一个字典）；或者
- 与其更新结构，不如替换它。
The former would look like:
前者看起来像：
class N(object):
def __init__(self, ind, set, v):
self.ind = ind
self.set = set
self.v = v
And the latter:
而后者：
item = items[node.ind]
items[node.ind] = N(item.ind, item.set, node.v)
Edit: if you want the latter, Ignacio's answer does the same thing more neatly using baked-in functionality.
编辑：如果你想要后者，伊格纳西奥的回答使用内置功能更巧妙地做同样的事情。
