python学习笔记（三）
不支持char，byte
repr 相当于反引号
id(x)
id(a)==id(b) <=> a is b
foostr='abcde'
foostr[::-1]='edcba'
foostr[::-2]='eca' //隔一个取一个
############ r'\n' '\n'################
>>> '\n'
'\n'
>>> print '\n'
>>> print r'\n'
\n
################ re 正则 ##################
import re
>>> m=re.search(r'\\[rtfvn]',r'Hello World\n')
>>> if m is not None:m.group()
...
'\\n'
############# 程序中出现字符串时加个u ################
>>> u'\1234'
u'S4'
>>> u'\u1234'
u'\u1234'
>>> str2='lmn'
>>> str3='xyz'
>>> max(str2)
'n'
>>> max(str2)
'n'
>>> min(str3)
'x'
>>> str='ab12MN'
>>> max(str)
'b'
############### enumerate ##################
>>> for i,t in enumerate(s):
... print i,t
...
0 f
1 o
2 o
3 b
4 a
5 r
>>> user_input=raw_input('Enter u name:')
Enter u name:wangweiwei
>>> print user_input
wangweiwei
############## isinstance ###################
>>> not isinstance('foo',unicode)
True
>>> isinstance(u'\0xAB',str)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: isinstance() arg 2 must be a class, type, or tuple of classes and types
>>> isinstance(u'',basestring)
True
>>> isinstance('foo',basestring)
True
>>>
######### capitalize,center,count,isspace,upper,lower ########################
>>> s='abc'
>>> s.capitalize()
'Abc'
>>> s.center(10)
' abc '
>>> s.count(s,0,12)
1
>>> s.isspace()
False
>>> s.upper()
'ABC'
>>> s.lower()
'abc'
############# split, join ########################
>>> queset='What\'s u favorite color?'
>>> queset.split()
["What's", 'u', 'favorite', 'color?']
>>> ':'.join(queset.split())
"What's:u:favorite:color?"
###########reversed#####################
s=['they','are','flowers']
>>> for t in reversed(s):
... print t
...
flowers
are
they
>>> sorted(s)
['are', 'flowers', 'they']
############ 将要使用str，chr的地方都使用unicode(),unichr()
#!/usr/bin/python
codec='utf-8'
filename='file.txt'
fp=open(filename,'w')
str=u'Hello World!\n'
str=str.encode(codec)
print str
fp.write(str)
fp.close()
hp=open(filename,'r')
str=hp.read()
hp.close()
str=str.decode(codec)
print str
################## append(),pop()
>>> cmp((4,2),(3,5))
1
########## 浅拷贝=> person[:] :拷贝，copy() 深拷贝：import copy copy.deepcopy()
>>> person=['a','b','c']
>>> habby=person[:]
>>> print habby
['a', 'b', 'c']
>>>
########### dict():创建字典 fromkeys():内建的创建字典的方法
fdict=dict((['x',1],['y',2]))
>>> ddict={}.fromkeys(('x','y'),-1)
>>> ddict
{'y': -1, 'x': -1}
#############访问字典中的键
>>> for key in ddict.keys():
... print 'key=%s,value=%s' %(key,ddict[key])
...
key=y,value=-1
key=x,value=-1
###############删除字典值del ddict['x'],ddict.clear()
###############dict.get()
############# dict.itere()
############# iteritems() , iterkeys() ,itervalues()
##################### 字典的update方法
>>> dic2={'a':'1','b':'2'}
>>> dic3={'c':'3','d':'4'}
>>> dic2.update(dic3)
>>> print dic2
{'a': '1', 'c': '3', 'b': '2', 'd': '4'}
>>> dic2.clear()
>>> print dic2
{}
>>>
########################setdefault():若字典中不存在此值，可当即设置上，若存在，则可以直接取到
##################fromkeys()
>>> {}.fromkeys('xyz')
{'y': None, 'x': None, 'z': None}
>>> {}.fromkeys(('love','honor'),True)
{'love': True, 'honor': True}
###########只有程序一运行便可以访问这三个文件sys.stdin,sys.stdout,sys.stderr
tempfile 用于生成临时的文件名
shutil 提供高级的文件访问功能
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