简单讲解Python中的闭包

#python 中的闭包
... def func(data):
...   count = [data]
...   def wrap():
...     count[0] += 1
...     return count[0]
...   return wrap
... 
... a = func(1)
>>> a()
5: 2
>>> a()
6: 3

 def func(x):
...   return lambda y :y+x
>>> b = func(1)
>>> b(1)
7: 2
>>> b(2)
8: 3
>>> print b #这里b是个function 在ruby中是proc
<function <lambda> at 0x01AC68F0>


 def addx(x):
... def adder (y): return x + y
... return adder
>>> add8 = addx(8)
>>> add8(8)
9: 16

def make_adder(addend):
  def adder(augend):
    return augend + addend
  return adder

p = make_adder(23)
q = make_adder(44)

print p(100)
print q(100)

123
144

def hellocounter (name):
  count=[0] 
  def counter():
    count[0]+=1
    print 'Hello,',name,',',str(count[0])+' access!'
  return counter

hello = hellocounter('ma6174')
hello()
hello()
hello() 

Hello, ysisl , 1 access!
Hello, ysisl , 2 access!
Hello, ysisl , 3 access!

def hellocounter (name):
  count=0 
  def counter():
    nonlocal count
    count+=1
    print 'Hello,',name,',',str(count[0])+' access!'
  return counter

hello = hellocounter('ma6174')
hello()
hello()
hello() 

def makebold(fn):
  def wrapped():
    return "<b>" + fn() + "</b>"
  return wrapped

def makeitalic(fn):
  def wrapped():
    return "<i>" + fn() + "</i>"
  return wrapped

@makebold
@makeitalic
def hello():
  return "hello world"

print hello() 

<b><i>hello world</i></b>