Instance()在Python中做什么?
这一行在python中做什么Instance()在Python中做什么?,python,python-2.7,python-3.x,Python,Python 2.7,Python 3.x,这一行在python中做什么 user_magics = Instance('IPython.core.magics.UserMagics', allow_none=True) 请注意,UserMagics是在IPython.core.magics.\uuuu init\uuuu.py中定义的空类,如下所示: @magics_class class UserMagics(Magics): """Placeholder for user-defined magics to be adde
user_magics = Instance('IPython.core.magics.UserMagics', allow_none=True)
请注意,UserMagics
是在IPython.core.magics.\uuuu init\uuuu.py
中定义的空类,如下所示:
@magics_class
class UserMagics(Magics):
"""Placeholder for user-defined magics to be added at runtime.
上述定义与此定义有何区别
user_magics = UserMagics()
注意,正如Blender在下面指出的,这是trailets包的一部分,而不是基本Python。
实例
是脚本的一部分。从文件中:
简而言之,traitlets允许用户定义具有
实例:
from traitlets import HasTraits, Int, Instance
class Foo(object):
pass
class MyObject(HasTraits):
num = Int()
foo = Instance(Foo, allow_none=True)
if __name__ == '__main__':
# works
a = MyObject()
a.num = 10
a.foo = Foo()
# works
b = MyObject()
b.num = 5
b.foo = None
# breaks
c = MyObject()
c.num = -1
c.foo = object() # The 'foo' trait of a MyObject instance must be a Foo or None, but a value of type 'object' was specified.
实例
是。从文件中:
简而言之,traitlets允许用户定义具有
具有类型检查和动态计算默认值的属性(特征)
当属性被修改时,特征会发出更改事件
Traitlets执行一些验证,并允许强制分配新的特征值。它们还允许用户定义自定义
基于其他属性值的属性验证逻辑
属性
下面是一个软件包的示例,特别是使用实例:
from traitlets import HasTraits, Int, Instance
class Foo(object):
pass
class MyObject(HasTraits):
num = Int()
foo = Instance(Foo, allow_none=True)
if __name__ == '__main__':
# works
a = MyObject()
a.num = 10
a.foo = Foo()
# works
b = MyObject()
b.num = 5
b.foo = None
# breaks
c = MyObject()
c.num = -1
c.foo = object() # The 'foo' trait of a MyObject instance must be a Foo or None, but a value of type 'object' was specified.
Instance
不是Python的一部分。它记录在traitlets
包中:Instance
不是Python的一部分。它记录在traitlets
包中:正是我要找的,谢谢Blender!更新了问题的标签,包括叛徒。正是我要找的,谢谢Blender!已更新问题的标记,以包括叛徒。