数据类型转换

In [1]: int(10)     
Out[1]: 10

In [3]: int(10.12)      ##小数的话 会取整数
Out[3]: 10

In [4]: int('asd')      ##定义字符串是错误的
---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-4-4e4d032af1ad> in <module>()
----> 1 int('asd')

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

有时候我们需要把字符串进行运算，字符串其实是不可以进行运算的，只有转换成10进制才可以进行运算。

In [5]: int('a',16)
Out[5]: 10

In [6]: int('0xa',16)
Out[6]: 10

hex(...)
    hex(number) -> string       ## hex括号内是个数字，转换成字符串。且字符串之间是不可以进行运算的。

In [7]: hex(10)
Out[7]: '0xa'

In [8]: hex(982)
Out[8]: '0x3d6'

In [10]: str(213)
Out[10]: '213'

#! /usr/bin/python

mac = '00:0c:29:9c:dc:41'       ##本地电脑的Mac地址
mac_prefix = mac[:-3]           ##取出Mac地址的前缀
last_two = mac[-2:]             ##取出MAC地址的后三位
plus_one = int(last_two, 16) + 1        ##把16进制的mac转换成10进制并+1
new_last_two = hex(plus_one)[-2:]       ##再次把10进制的mac地址转换成原来的16进制，如果不加[-2:]，则会出现 0x的前缀
new_mac = mac_prefix + ':' + new_last_two   ##把刚刚整理好的前缀和新的后两位拼接起来。
print new_mac

In [13]: int('01',16)
Out[13]: 1

'00:0c:29:9c:dc:2'

#! /usr/bin/python

mac = '00:0c:29:9c:dc:01'
mac_prefix = mac[:-3]
last_two = mac[-2:]
plus_one = int(last_two, 16) + 1
if plus_one in range(10):       ##判断是否在10以内
    new_last_two = hex(plus_one)[-1:]       ##截取最后一位
    new_last_two = '0' + new_last_two       ##输出的时候+0 连接起来
else:       ##如果不小于10以内就要恢复第一种情况
    new_last_two = hex(plus_one)[-2:]       ##第一种情况
new_mac = mac_prefix + ':' + new_last_two
print new_mac       ##在centos 6中的MAC全部是大写的，我们需要更改为  print new_mac.upper()

[[email protected] python]# python mac.py 
00:0c:29:9c:dc:xb

In [14]: int('0a',16)
Out[14]: 10

In [15]: hex(11)        ##加 1 后的值：
Out[15]: '0xb'

#! /usr/bin/python

mac = '00:0c:29:9c:dc:0a'
mac_prefix = mac[:-3]
last_two = mac[-2:]
plus_one = int(last_two, 16) + 1
if plus_one in range(10):
    new_last_two = hex(plus_one)[-1:]
    new_last_two = '0' + new_last_two
else:
    new_last_two = hex(plus_one)
    if len(new_last_two) == 3:      ##按照实际的情况把转换的值输出一下，然后按照长度或者其它方法筛选下即可。
        new_last_two = new_last_two[0] + new_last_two[2]
    else:
        new_last_two = new_last_two[2:]
new_mac = mac_prefix + ':' + new_last_two
print new_mac

In [19]: a = 'asd'

In [20]: list(a)
Out[20]: ['a', 's', 'd']

In [22]: list1 = list(a)

In [23]: list1
Out[23]: ['a', 's', 'd']

In [26]: ''.join(list1)
Out[26]: 'asd'

In [27]: '.'.join(list1)
Out[27]: 'a.s.d'

In [28]: a
Out[28]: 'asd'

In [29]: tuple(a)
Out[29]: ('a', 's', 'd')

In [30]: t = tuple(a)

In [31]: t
Out[31]: ('a', 's', 'd')

In [32]: ''.join(t)
Out[32]: 'asd'

In [33]: tuple(list1)
Out[33]: ('a', 's', 'd')

In [34]: list(t)
Out[34]: ['a', 's', 'd']

In [37]: dic
Out[37]: {'name': 'zhang', 'sex': 'man'}

In [38]: dic.items()        ##每个key都和value相互对应
Out[38]: [('name', 'zhang'), ('sex', 'man')]

In [42]: list1 = list(dic.items())

In [45]: dict(list1)
Out[45]: {'name': 'zhang', 'sex': 'man'}

In [39]: list1
Out[39]: ['a', 's', 'd']

In [40]: tuple(list1)
Out[40]: ('a', 's', 'd')

In [41]: dict(list1)
---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-41-5038e0d3cda6> in <module>()
----> 1 dict(list1)

ValueError: dictionary update sequence element #0 has length 1; 2 is required