The namespace in Python

Namespaces in Python are mappings of names (identifiers) to objects.

Specifically, Python holds a dictionary (__dict__) for modules, functions, classes, and objects, which is a mapping of rename-to-object.

You can see the output of the Python program below:

Print (' globals: ') print (Globals (). keys ()) print (") x = 1print (' globals after definition of x: ') print (Globals (). Keys ()) Print (") if x = = 1:    y = 2    z = 3    print (' Globals inside if:%s '% (Globals (). Keys ()))    print (' Locals inside I F:%s '% (locals (). Keys ())    del y    print (' Locals after del:%s '% (locals (). Keys ()))

In object-oriented programming, one of the biggest differences between Python and C + + is that namespace in Python can be dynamically changed, members of classes, members of class instances can be added dynamically, but simply add an item to the corresponding namespace dictionary. The values specifically noted here, functions (member functions or global functions) also have their own namespace dictionaries and can even be dynamically added

Class Test1 (object):    x = 1    def __init__ (self):        self.y =  2        self.z = 3    def func (self):        print (' Test ')    func.fx = 2print (test1.__dict__) t1 = Test1 () print (t1.__dict__) print (t1.func.__dict__)

As a result, we can understand what the so-called constructor __init__ in Python did, because the first member method passed in is a self reference, which is equivalent to

T1 = Test1 () calls test1.__init__ (T1) and then adds a T1 dictionary entry for class instance namespace in the constructor

The namespace in Python