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/
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)。
使用isinstance(object, type)。如上所述,如果你知道正确的类型,这很容易使用,例如,
isinstance('dog', str) ## gives bool True
但对于更深奥的对象,这可能很难使用。 例如:
import numpy as np
a = np.array([1,2,3])
isinstance(a,np.array) ## breaks
但你可以用这个技巧:
y = type(np.array([1]))
isinstance(a,y) ## gives bool True
所以我建议用你想检查的对象类型(例如,type(np.array())实例化一个变量(在本例中是y),然后使用isinstance。
因为type返回一个对象,所以可以使用object.name访问对象的名称
例子:
years = 5
user = {'name':'Smith', 'age':20}
print(type(a).__name__)
输出:“int”
print(type(b).__name__ )
输出:“东西”