71.md

rank	vote	view	answer	url
71	1679	895303	14	url

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在 Python 中如何得到对象的所有属性?

有没有什么方法可以检测对象是否有一个属性?例如:

>>> a = SomeClass()
>>> a.someProperty = value
>>> a.property
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: SomeClass instance has no attribute 'property'

怎么样才能在用 porperty 之前知道 a 有这个属性?

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试试 hasattr():

if hasattr(a, 'property'):
    a.property

答案2

hasattr 可以做到,但是我要说一句 Python 鼓励 "easier to ask for forgiveness than permission" (EAFP) 而不是 "look before you leap" (LBYL).详细查看下面链接:

EAFP vs LBYL (was Re: A little disappointed so far) EAFP vs. LBYL @Code Like a Pythonista: Idiomatic Python

例如:

try:
    doStuff(a.property)
except AttributeError:
    otherStuff()

要比下面的更好

if hasattr(a, 'property'):
    doStuff(a.property)
else:
    otherStuff()