[英]Is there a Python method to access all non-private and non-builtin attributes of a class?
I would like to call a method to give me a dict of all of the "non-private" (I use the term "private" somewhat loosely here since it does not really exist in Python) and non-builtin attributes (ie those that do not begin with a single or double underscore) on a class. 我想调用一种方法给我一个所有“非私有”的词典(我在这里使用“私有”一词,因为它在Python中并不存在)和非内置属性(即那些在类上不要以单个或双下划线开头。 Something like vars(MyClass) that would return only the "public" attributes on that class.
像vars(MyClass)这样的东西只能返回该类的“公共”属性。
I'm aware that 我知道
from M import *
does not import objects whose name starts with an underscore. 不会导入名称以下划线开头的对象。 ( http://www.python.org/dev/peps/pep-0008/#id25 ) How does import implement that?
( http://www.python.org/dev/peps/pep-0008/#id25 )导入如何实现? Via a builtin function or just by checking for underscores?
通过内置函数或仅通过检查下划线? What is the pythonic way to do this?
什么是pythonic方法呢?
Example: 例:
class MyClass(object):
def __init__(self):
do_stuff()
def _private(self):
print 'private'
def __gets_name_mangled(self:
print 'becomes _MyClass__gets_name_mangled()'
def public(self):
print 'public'
If I do 如果我做
vars(MyClass).keys()
I get 我明白了
['_MyClass__gets_name_mangled', '__module__', '_private', '__doc__', '__dict__', '__weakref__', 'public', '__init__']
How can I get only 我怎么才能得到
['public']
Or do I just need to check for underscores myself? 或者我只是需要自己检查下划线? It just seems like there would be a pythonic way to do this.
看起来似乎会有一种pythonic方式来做到这一点。
For more on underscores and double underscores, see: What is the meaning of a single- and a double-underscore before an object name? 有关下划线和双下划线的更多信息,请参阅: 对象名称之前的单下划线和双下划线的含义是什么?
Actually, it would be unpythonic for such function to exists - because "officially" there is no private or protected fields/properties in Python. 实际上,存在这样的函数将是unpythonic - 因为“正式”Python中没有私有或受保护的字段/属性。
While it makes sense to throw away module attributes with leading underscores (which are usually some implementation details) during import *
from some module*, it is not useful in context of any other object. 虽然在从某个模块*
import *
期间丢弃具有前导下划线(通常是一些实现细节)的模块属性是有意义的,但它在任何其他对象的上下文中都没有用。
So, if you need to list only "public" methods/attributes of an object, just iterate through result of dir
and drop names with leading underscores. 因此,如果您只需要列出对象的“公共”方法/属性,只需遍历
dir
结果并删除带有前导下划线的名称。
* "during import *
from some module'" *“在
import *
期间import *
从某些模块'”
Usually it is not the best practice. 通常这不是最好的做法。 Consider the next example:
考虑下一个例子:
module A
has a1
and a2
defined 模块
A
定义了a1
和a2
module B
has b1
and b2
defined 模块
B
定义了b1
和b2
This code in module C
works as expected: 模块
C
此代码按预期工作:
from A import a1, a2
from B import *
Imagine we add function a1
in module B
. 想象一下,我们在模块
B
添加了函数a1
。 Now suddenly module C
is broken, although we haven't touched it. 现在突然模块
C
坏了,虽然我们还没碰过它。
With a dict comprehension that filters vars() 使用dict理解过滤vars()
{ k:v for k,v in vars(myObject).items() if not k.startswith('_') }
Moved into a function that returns a list of attributes that are not 'soft private' or callables. 移动到一个函数,该函数返回非“软私有”或可调用的属性列表。 You can return values if you like by changing to dict comprehension as above
如果您愿意,可以通过更改为上述字典理解来返回值
def list_public_attributes(input_var):
return [k for k, v in vars(input_var).items() if
not (k.startswith('_') or callable(v))]
I'm using this function: 我正在使用这个功能:
def print_all_public_fields(obj):
print(obj)
for a in dir(obj):
if not a.startswith('_') and not a.isupper():
print('\t%s = %s' % (a, getattr(obj, a)))
I know it's not exactly what you want, but maybe it'll give you some idea. 我知道这不是你想要的,但也许它会给你一些想法。
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