所谓内置方法，就是凡是字符串都能用的方法，这个方法在创建字符串的类中，下面是总结：

　　首先，我们要学习一个获取帮助的内置函数 help(对象) ，对象可以是一个我们创建出来的，也可以是创建对象的那个类，类也是一个对象，被称为类对象。

　　当我们进入解释器的交互模式中输入以下代码时：

help(str)

　　其中，str就是创建字符串的类，然后我们就会得到一长串的结果：

Help on class str in module __builtin__:

class str(basestring)
 |  str(object='') -> string
 |  
 |  Return a nice string representation of the object.
 |  If the argument is a string, the return value is the same object.
 |  
 |  Method resolution order:
 |      str
 |      basestring
 |      object
 |  
 |  Methods defined here:
 |  
 |  __add__(...)
 |      x.__add__(y) <==> x+y　　#字符串拼接，看+号就知道
 |  
 |  __contains__(...)
 |      x.__contains__(y) <==> y in x　　#判断x里字符是否在y里
 |  
 |  __eq__(...)
 |      x.__eq__(y) <==> x==y　　
 |  
 |  __format__(...)
 |      S.__format__(format_spec) -> string
 |      
 |      Return a formatted version of S as described by format_spec.
 | 
 |  __ge__(...)
 |      x.__ge__(y) <==> x>=y
 |  
 |  __getattribute__(...)
 |      x.__getattribute__('name') <==> x.name　　#获取属性
 |  
 |  __getitem__(...)
 |      x.__getitem__(y) <==> x[y]　　#索引取值，详情参考python中的序列
 |  
 |  __getnewargs__(...)
 |  
 |  __getslice__(...)
 |      x.__getslice__(i, j) <==> x[i:j]　　#切片，也是序列的一种方法
 |      
 |      Use of negative indices is not supported.
 |  
 |  __gt__(...)
 |      x.__gt__(y) <==> x>y
 |  
 |  __hash__(...)
 |      x.__hash__() <==> hash(x)　　
 |  
 |  __le__(...)
 |      x.__le__(y) <==> x<=y
 |  
 |  __len__(...)
 |      x.__len__() <==> len(x)
 |  
 |  __lt__(...)
 |      x.__lt__(y) <==> x<y
 |  
 |  __mod__(...)
 |      x.__mod__(y) <==> x%y
 |  
 |  __mul__(...)
 |      x.__mul__(n) <==> x*n
 |  
 |  __ne__(...)
 |      x.__ne__(y) <==> x!=y
 |  
 |  __repr__(...)
 |      x.__repr__() <==> repr(x)
 |  
 |  __rmod__(...)
 |      x.__rmod__(y) <==> y%x
 |  
 |  __rmul__(...)
 |      x.__rmul__(n) <==> n*x
 |  
 |  __sizeof__(...)
 |      S.__sizeof__() -> size of S in memory, in bytes　　#用字节表示在内存中的大小
 |  
 |  __str__(...)
 |      x.__str__() <==> str(x)
 |  
 |  capitalize(...)
 |      S.capitalize() -> string
 |      '''返回首字母大写字符串副本,对中文无效'''
 |      Return a copy of the string S with only its first character
 |      capitalized.
 |  
 |  center(...)
 |      S.center(width[, fillchar]) -> string
 |      '''返回指定宽度（width）的字符串副本，原字符串居中对齐，可指定用什么来填充多余部分（fillchar）默认为空格，关于对齐和填充可以看上篇博文的解释'''
 |      Return S centered in a string of length width. Padding is
 |      done using the specified fill character (default is a space)
 |  
 |  count(...)
 |      S.count(sub[, start[, end]]) -> int
 |      '''计数器，返回给定字符串在原字符串出现的次数，也可指定范围'''
 |      Return the number of non-overlapping occurrences of substring sub in
 |      string S[start:end].  Optional arguments start and end are interpreted
 |      as in slice notation.
 |  
 |  decode(...)
 |      S.decode([encoding[,errors]]) -> object
 |      '''解码，将字符串解码成某种字符集'''
 |      Decodes S using the codec registered for encoding. encoding defaults
 |      to the default encoding. errors may be given to set a different error
 |      handling scheme. Default is 'strict' meaning that encoding errors raise
 |      a UnicodeDecodeError. Other possible values are 'ignore' and 'replace'
 |      as well as any other name registered with codecs.register_error that is
 |      able to handle UnicodeDecodeErrors.
 |  
 |  encode(...)
 |      S.encode([encoding[,errors]]) -> object
 |      '''编码,将字符串编码'''
 |      Encodes S using the codec registered for encoding. encoding defaults
 |      to the default encoding. errors may be given to set a different