基本上我想这样做:
obj = 'str'
type ( obj ) == string
我试着:
type ( obj ) == type ( string )
但这并没有起作用。
还有,其他类型的呢?例如,我无法复制NoneType。
基本上我想这样做:
obj = 'str'
type ( obj ) == string
我试着:
type ( obj ) == type ( string )
但这并没有起作用。
还有,其他类型的呢?例如,我无法复制NoneType。
当前回答
要获取类型,使用__class__成员,如unknown_thing.__class__
Talk of duck-typing is useless here because it doesn't answer a perfectly good question. In my application code I never need to know the type of something, but it's still useful to have a way to learn an object's type. Sometimes I need to get the actual class to validate a unit test. Duck typing gets in the way there because all possible objects have the same API, but only one is correct. Also, sometimes I'm maintaining somebody else's code, and I have no idea what kind of object I've been passed. This is my biggest problem with dynamically typed languages like Python. Version 1 is very easy and quick to develop. Version 2 is a pain in the buns, especially if you didn't write version 1. So sometimes, when I'm working with a function I didn't write, I need to know the type of a parameter, just so I know what methods I can call on it.
这就是__class__参数派上用场的地方。这(据我所知)是获取对象类型的最佳方法(可能是唯一的方法)。
其他回答
我想这个就可以了
if isinstance(obj, str)
isinstance()
在你的例子中,isinstance("this is a string", str)将返回True。
你可能还想读这个:http://www.canonical.org/~kragen/isinstance/
您可以比较类的检查级别。
#!/usr/bin/env python
#coding:utf8
class A(object):
def t(self):
print 'A'
def r(self):
print 'rA',
self.t()
class B(A):
def t(self):
print 'B'
class C(A):
def t(self):
print 'C'
class D(B, C):
def t(self):
print 'D',
super(D, self).t()
class E(C, B):
pass
d = D()
d.t()
d.r()
e = E()
e.t()
e.r()
print isinstance(e, D) # False
print isinstance(e, E) # True
print isinstance(e, C) # True
print isinstance(e, B) # True
print isinstance(e, (A,)) # True
print e.__class__ >= A, #False
print e.__class__ <= C, #False
print e.__class__ < E, #False
print e.__class__ <= E #True
你很接近了!字符串是模块,不是类型。你可能想比较obj的类型和字符串的类型对象,即str:
type(obj) == str # this works because str is already a type
另外:
type(obj) == type('')
注意,在python2中,如果obj是unicode类型,那么上述两种方法都不能工作。isinstance()也不会。看看约翰对这篇文章的评论,了解如何解决这个问题……我已经试着记住它大约10分钟了,但是有一个记忆块!
使用str代替string
type ( obj ) == str
解释
>>> a = "Hello"
>>> type(a)==str
True
>>> type(a)
<type 'str'>
>>>