python基础学习笔记

 

python基础学习笔记

数字自加操作

python基础学习笔记
>>> n=1
>>> n=n+1
>>> print n
2
>>> n += 1
>>> print n
3
python基础学习笔记

格式化输出数字

python基础学习笔记
>>> print float n:%f\ninit  n:%d % (n,n)
float n:3.000000
init  n:3
>>> print %0.3f % n
3.000
>>> print %0.4f % n
3.0000
>>>
python基础学习笔记

 

字符串切片操作

python基础学习笔记
>>> s = football
>>> s[0]
f
>>> s[0:]
football
>>> s[1:]
ootball
>>> s[1:2]
o
>>> s[:3]
foo
>>> s[1:1]
‘‘
>>> s[1:-1]
ootball
>>> s[1:0]
‘‘
python基础学习笔记

 

字符串加法和乘法

python基础学习笔记
>>> s *2
footballfootball
>>> s += a
>>> s
footballa
>>> print -*20
--------------------
>>> print -*40
----------------------------------------
python基础学习笔记

 

列表切片与元素赋值操作

python基础学习笔记
>>> alist = [a,b,c,d,e]
>>> print alist
[a, b, c, d, e]
>>> alist[0]
a
>>> alist[1:-1]
[b, c, d]
>>> alist[1:3]
[b, c]
>>> alist[:3]
[a, b, c]
>>> alist[0]=f
>>> alist
[f, b, c, d, e]
>>>
python基础学习笔记

 

元组切片操作

注:元组中的元素不能重新赋值

python基础学习笔记
>>> 
>>> aTuple = (1,2,3,4,5,6)
>>> aTuple
(1, 2, 3, 4, 5, 6)
>>> aTuple[:3]
(1, 2, 3)
>>> aTuple[5]=4
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: tuple object does not support item assignment
python基础学习笔记

 

字典赋值、读取、更新和key操作

python基础学习笔记
>>> hostdict={name:server01,ip:192.168.10.10,port:8080}
>>> hostdict
{ip: 192.168.10.10, name: server01, port: 8080}
>>> hostdict[name]
server01
>>> hostdict[ip]=192.168.10.11
>>> hostdict
{ip: 192.168.10.11, name: server01, port: 8080}
>>> hostdict.keys()
[ip, name, port]
>>> for key in hostdict:
...     print %s\t%s % (key,hostdict[key])
... 
ip        192.168.10.11
name      server01
port      8080
>>>
python基础学习笔记

 

列表解析

python基础学习笔记
>>> a=[x + 2 for x in range(5)]
>>> a
[2, 3, 4, 5, 6]
>>> b=[x * 2 for x in s]
>>> b
[ff, oo, oo, tt, bb, aa, ll, ll]
>>> c =[x ** 2 for x in range(8) if x % 2]
>>> c
[1, 9, 25, 49]
>>>
python基础学习笔记

 

dir操作获取模块的方法和属性

python基础学习笔记
>>> import sys
>>> dir(sys)
[__displayhook__, __doc__, __egginsert, __excepthook__, __name__, __package__, __plen, __stderr__, __stdin__, __stdout__, _clear_type_cache, _current_frames, _getframe, api_version, argv, builtin_module_names, byteorder, call_tracing, callstats, copyright, displayhook, dont_write_bytecode, exc_clear, exc_info, exc_type, excepthook, exec_prefix, executable, exit, flags, float_info, getcheckinterval, getdefaultencoding, getdlopenflags, getfilesystemencoding, getprofile, getrecursionlimit, getrefcount, getsizeof, gettrace, hexversion, last_traceback, last_type, last_value, maxint, maxsize, maxunicode, meta_path, modules, path, path_hooks, path_importer_cache, platform, prefix, ps1, ps2, py3kwarning, setcheckinterval, setdlopenflags, setprofile, setrecursionlimit, settrace, stderr, stdin, stdout, subversion, version, version_info, warnoptions]
>>> print sys.getfilesystemencoding
<built-in function getfilesystemencoding>
>>> print sys.getfilesystemencoding()
UTF-8
>>>
python基础学习笔记

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python基础学习笔记

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