python必知必会

>>> answer = ‘tell me‘
>>> def foo():
...     answer = ‘42‘
...     print answer
...
>>> foo()
42
>>> print answer
tell me
>>>

>>>f = lambda x:x+y
>>>f(1)
>>>2

>>> def f1():
...     answer = ‘tell me‘
...     def f2():
...         print answer
...     f2()
...
>>> f1()
tell me
>>> 

>>> answer = ‘tell me‘
>>> def foo():
...     global answer
...     answer = ‘42‘
...     print answer
... 
>>> print answer
tell me
>>> foo()
42
>>> print answer
42

#test_example.py
TEST_NUM = 2
TEST_STR = " test_str "
if __name__ == ‘__main__‘:
    print __name__
    print TEST_STR

>>> import test_example as t
>>> t.TEST_NUM
2
>>> t.__name__
‘test_example‘
>>> type(t)
<type ‘module‘>
>>> dir(t)
[‘TEST_NUM‘, ‘TEST_STR‘, ‘__builtins__‘, ‘__doc__‘, ‘__file__‘, ‘__name__‘, ‘__package__‘]

def my_dec(func):
     def wrapper():
          print ‘before decorator‘
          func()
          print ‘after decorator‘
     return wrapper
 
def hello():
     print ‘hello‘

@my_dec
def hello():
     print ‘hello‘

def hello():
     print ‘hello‘
hello = my_dec(hello)

def my_dec(func):
     def wrapper(*arg, **kwargs):
          print arg, kwargs
          print ‘before decorator‘
          func(*arg,**kwargs)
          print ‘after decorator‘
     return wrapper

@my_dec
def hello(*arg, **kwargs):
     print ‘in hello‘
     print arg, kwargs
     print ‘in hello‘

if __name__ == ‘__main__‘:
     hello(‘the answer is ‘, 42) 

@wraps(func)

def coroutine():
     while True:
          y = yield
          print y
 
c=coroutine()
c.send(None)
c.send(1)
c.send(2)
c.send(None)

li=["a","s","d","f"]
for idx, ele in enumerate(li):
     print idx, ele

class Foo:
    def __init__(self):
        self.a = 1
f=Foo()
f.__class__.__name__
type(f)

>>> di={}
>>> dir(di)        #居家旅行必备的dir  
 
>>> class Foo:
...     """
...        hello from Foo
...     """
...     def __init__(self):
...         self.a = 1
...         self.b = ‘2‘
...     def reset(self):
...         self.c = 0
... 
>>> f=Foo()
>>> Foo.__dict__
{‘reset‘: <function reset at 0x8e8d1b4>, ‘__module__‘: ‘__main__‘, ‘__doc__‘: ‘\n       hello from Foo\n    ‘, ‘__init__‘: <function __init__ at 0x8e8d294>}
>>> f.__dict__          #拿到object的属性
{‘a‘: 1, ‘b‘: ‘2‘}
>>> f.reset()
>>> f.__dict__          #属性还能动态增加！似乎很神奇。
{‘a‘: 1, ‘c‘: 0, ‘b‘: ‘2‘}
>>>