python编码-2

字典

>>> aa={}

>>> aa['wo']=[1,2,3,4]

>>> aa['ni']=[5,6,7,8]

>>> aa['zhang']=[20,'it','jp']

>>> aa['wu']=[30,'hr','cn']

>>> aa

{'wo': [1, 2, 3, 4], 'ni': [5, 6, 7, 8], 'wu': [30, 'hr', 'cn'], 'zhang': [20, 'it', 'jp']}

遍历字典，将字典中的一个元素的key-value对分别打出

>>> for name,info in aa.items():

...     print name,info

...

wo [1, 2, 3, 4]

ni [5, 6, 7, 8]

wu [30, 'hr', 'cn']

zhang [20, 'it', 'jp']

打出值（是一个列表）的第一个字段

>>> for name,info in aa.items():

...     print name,info[0]

...

wo 1

ni 5

wu 30

zhang 20

遍历字典
>>> name
{'r': 12, 'b': 23}
>>> for k,v in name.items():
...     print k,v
...
r 12
b 23

函数

这是第一个函数
[root@kvm1 python]# python fun1.py

hello,wudealex,how are you?

[root@kvm1 python]# cat fun1.py

def sayHi(name):

        print "hello,%s,how are you?" %name

n="wudealex"

sayHi(n)

这是第二个函数

[root@kvm1 python]# cat fun2.py

def sayHi(age):

        if age >20:

                print 'you are too old'

        else:

                print 'you are a young man'

n=int(raw_input('please input your age!!! '))

sayHi(n)

正常情况

[root@kvm1 python]# python fun2.py

please input your age!!! 23

you are too old

[root@kvm1 python]# python fun2.py

please input your age!!! 12

you are a young man

满足了基本功能

但却有三个主要问题

其一输入字符会报错并退出

其二不输入会报错并退出

其三不能循环等待用户输入，一次就退出

[root@kvm1 python]# python fun2.py

please input your age!!! f

Traceback (most recent call last):

  File "fun.py", line 7, in <module>

    n=int(raw_input('please input your age!!! '))

ValueError: invalid literal for int() with base 10: 'f'

[root@kvm1 python]# python fun2.py

please input your age!!!

Traceback (most recent call last):

  File "fun.py", line 7, in <module>

    n=int(raw_input('please input your age!!! '))

ValueError: invalid literal for int() with base 10: ''

这是对第二个函数的改进版，解决了存留的bug

[root@kvm1 python]# cat fun3.py

def sayHi():
        while True:
                try:
                        age=int(raw_input('please input your \033[42;31m age \033[0m!!! '))
                        break
                except ValueError:
                        print 'please input a \033[46;33m number \033[0m,not string.'
        if age >20:
                print 'you are a \033[41;32m old \033[0m man '
        else:
                print 'you are a \033[43;34m young \033[0m man'

sayHi()

[root@kvm1 python]# python fun3.py

please input your age!!!

please input a number,not string.

please input your age!!! e

please input a number,not string.

please input your age!!! w

please input a number,not string.

please input your age!!! -

please input a number,not string.

please input your age!!! 12

you are a young man

[root@kvm1 python]# python fun1.py

please input your age!!! 34

you are too old

函数的默认参数，

即c=0

或空c=''

import os

def sshcmd(a,b,c):

        sh= 'ssh %s@%s %s' %(a,b,c)

#       print sh

        os.system(sh)

user='root'

host='192.168.10.103'

cmd='hostname'

sshcmd(user,host,cmd)

pickle模块

pickle序列化，不像文件，plk文件不需要转来转去，如果用文件来中转的话，需要遍历字典，还要输出到文件中，读的时候也较麻烦

所以pickle模块提供了一种中间物，方便共享数据。原样存，原样取。便于移植

定义

>>> import tab

>>> import pickle

>>> acc={}

>>> acc['']=['a',15,14]

>>> acc['']=['b',30,40]

>>> acc

{'': ['a', 15, 14], '': ['b', 30, 40]}

>>> f =file('acc.pkl','wb')

>>> pickle.dump(acc,f)

>>> f.close()

假如pickle.dump后，又需要修改某个值，

acc[''][0]='c'

这个时候如果再一次的

pickle.dump(acc,f),那么acc.pkl文件会有两组字典，所以会对load时产生混乱，

所以最好dump一次就close一次，再修改，再打开

取用

>>> pkl_file=open('acc.pkl','rb')

>>> acc_info=pickle.load(pkl_file)

>>> acc_info

{'': ['a', 15, 14], '': ['b', 30, 40]}

re模块

>>> m=re.match(r'ni','ni hao')

>>> print m.group()

ni

>>> m=re.match(r'ii','ni hao')

>>> print m.group()

Traceback (most recent call last):

  File "<stdin>", line 1, in <module>

AttributeError: 'NoneType' object has no attribute 'group'

>>> p=re.compile(r'\d+')

>>> print p.split('one1two2three3four4')

['one', 'two', 'three', 'four', '']

>>> p=re.compile(r'\D+')

>>> print p.split('one1two2three3four4')

['', '', '', '', '']