python 如何通过 __dict__ 分配新的类属性？
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时间：2020-11-03 20:05:32 来源:igfitidea点击:
How to assign a new class attribute via __dict__?
提问by Philipp der Rautenberg
I want to assign a class attribute via a string object - but how?
我想通过字符串对象分配一个类属性 - 但如何？
Example:
例子：
class test(object):
pass
a = test()
test.value = 5
a.value
# -> 5
test.__dict__['value']
# -> 5
# BUT:
attr_name = 'next_value'
test.__dict__[attr_name] = 10
# -> 'dictproxy' object does not support item assignment
回答by gak
There is a builtin function for this:
为此有一个内置函数：
setattr(test, attr_name, 10)
Reference: http://docs.python.org/library/functions.html#setattr
参考：http: //docs.python.org/library/functions.html#setattr
Example:
例子：
>>> class a(object): pass
>>> a.__dict__['wut'] = 4
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: 'dictproxy' object does not support item assignment
>>> setattr(a, 'wut', 7)
>>> a.wut
7
