import multiprocessing as mp

def test(msg):
    print msg

p = mp.Pool(processes = 5) # 创建5条进程

for i in range(10):
    msg = 'hello-%d'%i
    p.apply_async(test, (msg, )) # 向进程池添加任务

p.close() # 关闭进程池，不再接受请求
p.join() # 等待所有的子进程结束

import threadpool
def func(a, b, c):
      print a, b, c
pool = threadpool.ThreadPool(20, poll_timeout=None)
lst = []
for i in range(500):
      dic = {"a": i, "b": i+1, "c": i}
      pair = (None, dic)
      lst.append(pair)

requests = threadpool.makeRequests(func, lst)
[pool.putRequest(req) for req in requests]
pool.wait()

pool = threadpool.ThreadPool(20, poll_timeout=None)

>>> import copy
>>> origin = 1
>>> cop1 = copy.copy(origin) 
#cop1 是 origin 的shallow copy
>>> cop2 = copy.deepcopy(origin) 
#cop2 是 origin 的 deep copy
>>> origin = 2
>>> origin
2
>>> cop1
1
>>> cop2
1
#cop1 和 cop2 都不会随着 origin 改变自己的值
>>> cop1 == cop2
True
>>> cop1 is cop2
True

>>> import copy
>>> origin = [1, 2, [3, 4]]
#origin 里边有三个元素：1， 2，[3, 4]
>>> cop1 = copy.copy(origin)
>>> cop2 = copy.deepcopy(origin)
>>> cop1 == cop2
True
>>> cop1 is cop2
False 
#cop1 和 cop2 看上去相同，但已不再是同一个object
>>> origin[2][0] = "hey!" 
>>> origin
[1, 2, ['hey!', 4]]
>>> cop1
[1, 2, ['hey!', 4]]
>>> cop2
[1, 2, [3, 4]]
#把origin内的子list [3, 4] 改掉了一个元素，观察 cop1 和 cop2

# 把 [1, 2, 3] 看成一个物品。a = [1, 2, 3] 就相当于给这个物品上贴上 a 这个标签。而 b = a 就是给这个物品又贴上了一个 b 的标签。
>>> a = [1, 2, 3]
>>> b = a
>>> a = [4, 5, 6] # 赋新的值给 a
>>> a
[4, 5, 6]
>>> b
[1, 2, 3]
# a 的值改变后，b 并没有随着 a 变。
# a = [4, 5, 6] 就相当于把 a 标签从 [1 ,2, 3] 上撕下来，贴到了 [4, 5, 6] 上。
# 在这个过程中，[1, 2, 3] 这个物品并没有消失。 b 自始至终都好好的贴在 [1, 2, 3] 上，既然这个 reference 也没有改变过。 b 的值自然不变。

>>> a = [1, 2, 3]
>>> b = a
>>> a[0], a[1], a[2] = 4, 5, 6 # 改变原来 list 中的元素
>>> a
[4, 5, 6]
>>> b
[4, 5, 6]
# a 的值改变后，b 随着 a 变了
# a[0], a[1], a[2] = 4, 5, 6 则是直接改变了 [1, 2, 3] 这个物品本身。把它内部的每一部分都重新改装了一下。内部改装完毕后，[1, 2, 3] 本身变成了 [4, 5, 6]。
# 而在此过程当中，a 和 b 都没有动，他们还贴在那个物品上。因此自然 a b 的值都变成了 [4, 5, 6]。

a=[1,2]
b=[2,3]
a.append(b)
b.append(a)
DEL a
DEL b

a=[1,3]
b=[2,4]
a.append(b)
b.append(a)
del a
del b

a=[1,3]
b=[2,4]
a.append(b)
b.append(a)
del a

import collections
d1 = collections.OrderedDict()
d1['a'] = 'A'
d1['2'] = '2'
d1['c'] = 'C'
d1['b'] = 'B'
d1['1'] = '1'
for k,v in d1.items():
    print k,v

d1 = {}
d1['a'] = 'A'
d1['2'] = '2'
d1['c'] = 'C'
d1['b'] = 'B'
d1['1'] = '1'
print "xxx"
for k,v in d1.items():
    print k,v

#输出
a A
2 2
c C
b B
1 1
xxx
a A
1 1
c C
2 2
b B

import collections
d1 = collections.OrderedDict()
d1['a'] = 'A'
d1['2'] = '2'

d2 = collections.OrderedDict()
d2['2'] = '2'
d2['a'] = 'A'

print d2 == d1 ## False

bufsize = 0
f = open('file.txt', 'w', buffering=bufsize)

def test_args(first, *args):
   print 'Required argument: ', first
   for v in args:
      print 'Optional argument: ', v

test_args(1, 2, 3, 4)
# result:
# Required argument: 1
# Optional argument:  2
# Optional argument:  3
# Optional argument:  4

def test_kwargs(first, *args, **kwargs):
   print 'Required argument: ', first
   for v in args:
      print 'Optional argument (*args): ', v
   for k, v in kwargs.items():
      print 'Optional argument %s (*kwargs): %s' % (k, v)

test_kwargs(1, 2, 3, 4, k1=5, k2=6)
# results:
# Required argument:  1
# Optional argument (*args):  2
# Optional argument (*args):  3
# Optional argument (*args):  4
# Optional argument k2 (*kwargs): 6
# Optional argument k1 (*kwargs): 5

def test_args(first, second, third, fourth, fifth):
    print 'First argument: ', first
    print 'Second argument: ', second
    print 'Third argument: ', third
    print 'Fourth argument: ', fourth
    print 'Fifth argument: ', fifth

# Use *args
args = [1, 2, 3, 4, 5]
test_args(*args)
# results:
# First argument:  1
# Second argument:  2
# Third argument:  3
# Fourth argument:  4
# Fifth argument:  5

# Use **kwargs
kwargs = {
    'first': 1,
    'second': 2,
    'third': 3,
    'fourth': 4,
    'fifth': 5
}

test_args(**kwargs)
# results:
# First argument:  1
# Second argument:  2
# Third argument:  3
# Fourth argument:  4
# Fifth argument:  5