Python 类与作用域——一些测试

/* 一 */
>>> class T ():
        a = 0
        b = a
    
>>> T.b
0
>>> del T


/* 二 */
>>> class T ():
        a = 0
        b = T.a

Traceback (most recent call last):
  File "<pyshell#9>", line 1, in <module>
    class T ():
  File "<pyshell#9>", line 3, in T
    b = T.a
NameError: name ‘T‘ is not defined


/* 三 */
>>> class T ():
        def a (self):
            print (‘a‘)
        def ab (self):
            a (self)
            print (‘b‘)

>>> T.ab (‘test‘)
Traceback (most recent call last):
  File "<pyshell#19>", line 1, in <module>
    T.ab (‘test‘)
  File "<pyshell#18>", line 5, in ab
    a (self)
NameError: name ‘a‘ is not defined
>>> del T


/* 四 */
>>> class T ():
        def a (self):
            print (‘a‘)
        def ab (self):
            T.a (self)
            print (‘b‘)
        
>>> T.ab (‘test‘)
a
b
>>> del T


/* 五 */
>>> class T ():
        a = 0
        def pa (self):
            print (a)
    
>>> T.pa (‘test‘)
Traceback (most recent call last):
  File "<pyshell#27>", line 1, in <module>
    T.pa (‘test‘)
  File "<pyshell#25>", line 4, in pa
    print (a)
NameError: name ‘a‘ is not defined
>>> del T


/* 六 */
>>> class T ():
    a = 0
    def pa (self):
        print (T.a)

>>> T.pa (‘test‘)
0
>>> del T
>>>