Python——str(字符串)内部功能介绍

str内部功能详解：

 class str(object):
     """
     str(object='') -> str
     str(bytes_or_buffer[, encoding[, errors]]) -> str

     Create a new string object from the given object. If encoding or
     errors is specified, then the object must expose a data buffer
     that will be decoded using the given encoding and error handler.
     Otherwise, returns the result of object.__str__() (if defined)
     or repr(object).
     encoding defaults to sys.getdefaultencoding().
     errors defaults to 'strict'.
     """

     def capitalize(self):  # real signature unknown; restored from __doc__
         """
         S.capitalize() -> str

         Return a capitalized version of S, i.e. make the first character
         have upper case and the rest lower case.
         """
         return
     # 首字母大写
     # >>> a = "abel"
     # >>> b = a.capitalize()
     # >>> b
     # 'Abel'

     def casefold(self):  # real signature unknown; restored from __doc__
         """
         S.casefold() -> str

         Return a version of S suitable for caseless comparisons.
         """
         return ""
     # 首字母大写变小写
     # >>> a = "Abel"
     # >>> b = a.casefold()
     # >>> b
     # 'abel'

     def center(self, width, fillchar=None):  # real signature unknown; restored from __doc__
         """
         S.center(width[, fillchar]) -> str

         Return S centered in a string of length width. Padding is
         done using the specified fill character (default is a space)
         """
         return ""
     # 内容居中,width: 总长度; fillchar:空白处填充内容,默认无
     # >>> a
     # 'Abel'
     # >>> b = a.center(20, '#')
     # >>> b
     # '########Abel########'

     def count(self, sub, start=None, end=None):  # real signature unknown; restored from __doc__
         """
         S.count(sub[, start[, end]]) -> int

         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.
         """
         return 0
     # 子序列个数
     # >>> a = "Abelisgood"
     # >>> b = a.count('o')
     # >>> b
     #
     # >>> b = a.count('o', 0, 8)
     # >>> b
     #
     def encode(self, encoding='utf-8', errors='strict'):  # real signature unknown; restored from __doc__
         """
         S.encode(encoding='utf-8', errors='strict') -> bytes

         Encode S using the codec registered for encoding. Default encoding
         is 'utf-8'. errors may be given to set a different error
         handling scheme. Default is 'strict' meaning that encoding errors raise
         a UnicodeEncodeError. Other possible values are 'ignore', 'replace' and
         'xmlcharrefreplace' as well as any other name registered with
         codecs.register_error that can handle UnicodeEncodeErrors.
         """
         return b""
     # 编码,针对unicode

     def endswith(self, suffix, start=None, end=None):  # real signature unknown; restored from __doc__
         """
         S.endswith(suffix[, start[, end]]) -> bool

         Return True if S ends with the specified suffix, False otherwise.
         With optional start, test S beginning at that position.
         With optional end, stop comparing S at that position.
         suffix can also be a tuple of strings to try.
         """
         return False
     # 判断str是否以xxx 结束
     # >>> a
     # 'Abelisgood'
     # >>> b = a.endswith('d')
     # >>> b
     # True
     # >>> b = a.endswith('g', 0, 7)
     # >>> b
     # True
     def expandtabs(self, tabsize=8):  # real signature unknown; restored from __doc__
         """
         S.expandtabs(tabsize=8) -> str

         Return a copy of S where all tab characters are expanded using spaces.
         If tabsize is not given, a tab size of 8 characters is assumed.
         """
         return ""
     # 将tab转换成空格,默认一个tab转换成8个空格
     # >>> a = "a\tbel"
     # >>> b= a.expandtabs()
     # >>> b
     # 'a       bel'(8个空格)
     def find(self, sub, start=None, end=None):  # real signature unknown; restored from __doc__
         """
         S.find(sub[, start[, end]]) -> int

         Return the lowest index in S where substring sub is found,
         such that sub is contained within S[start:end].  Optional
         arguments start and end are interpreted as in slice notation.

         Return -1 on failure.
         """
         return 0
     # 寻找子序列位置,如果没有找到,返回-1
     # index没有找到,直接报错
     # >>> a = "asdfjsdakfwejfi"
     # >>> b = a.find('f', 0, 11)
     # >>> b
     #
     # >>> b = a.find('z')
     # >>> b
     # -1
     def format(self, *args, **kwargs):  # known special case of str.format
         """
         S.format(*args, **kwargs) -> str

         Return a formatted version of S, using substitutions from args and kwargs.
         The substitutions are identified by braces ('{' and '}').
         """
         pass
     # 字符串格式化,动态参数。可以拼接字符串。
     # >>> a = "abel {0} good {1}"
     # >>> b = a.format('is', 'man')
     # >>> b
     # 'abel is good man'
     # >>>
     def format_map(self, mapping):  # real signature unknown; restored from __doc__
         """
         S.format_map(mapping) -> str

         Return a formatted version of S, using substitutions from mapping.
         The substitutions are identified by braces ('{' and '}').
         """
         return ""

     def index(self, sub, start=None, end=None):  # real signature unknown; restored from __doc__
         """
         S.index(sub[, start[, end]]) -> int

         Like S.find() but raise ValueError when the substring is not found.
         """
         return 0
     # 返回索引位置;可先参数，start:起始位置，end:结束位置，返回一个整数类型(当字符串没有找到时，会提示报错信息)
     # >>> a = "asdfjsdakfwejfi"
     # >>> b = a.index('z')
     # Traceback (most recent call last):
     # File "<pyshell#22>", line 1, in <module>
     #     b = a.index('z')
     # ValueError: substring not found
     def isalnum(self):  # real signature unknown; restored from __doc__
         """
         S.isalnum() -> bool

         Return True if all characters in S are alphanumeric
         and there is at least one character in S, False otherwise.
         """
         return False
     # 字符串都是字符，数字 或是字符数字组合则为True否则为False
     # >>> a
     # 'asdfjsdakfwejfi'
     # >>> b = a.isalnum()
     # >>> b
     # True

     # >>> a = ' '
     # >>> b = a.isalnum()
     # >>> b
     # False
     def isalpha(self):  # real signature unknown; restored from __doc__
         """
         S.isalpha() -> bool

         Return True if all characters in S are alphabetic
         and there is at least one character in S, False otherwise.
         """
         return False
     # 字符串中有一个为字母或所有都是字母都 True 否则为False
     # >>> a
     # 'abel20'
     # >>> b = a.isalpha()
     # >>> b
     # False

     def isdecimal(self):  # real signature unknown; restored from __doc__
         """
         S.isdecimal() -> bool

         Return True if there are only decimal characters in S,
         False otherwise.
         """
         return False
     # 如果只有十进制则返回True，否则返回False
     # >>> a = 'abel20'
     # >>> b = a.isdecimal()
     # >>> b
     # False

     def isdigit(self):  # real signature unknown; restored from __doc__
         """
         S.isdigit() -> bool

         Return True if all characters in S are digits
         and there is at least one character in S, False otherwise.
         """
         return False
     # 元素全部为数字时返回 True否则返回 False
     # >>> a
     # 'abel20'
     # >>> b = a.isdigit()
     # >>> b
     # False    

     def isidentifier(self):  # real signature unknown; restored from __doc__
         """
         S.isidentifier() -> bool

         Return True if S is a valid identifier according
         to the language definition.

         Use keyword.iskeyword() to test for reserved identifiers
         such as "def" and "class".
         """
         return False
     # 判断字符串是否是合法的标识符(标识符必须合法)返回bool类型
     # >>> a = '5'
     # >>> b = a.isidentifier()
     # >>> b
     # False
     # >>> a = 'abel342'
     # >>> b = a.isidentifier()
     # >>> b
     # True
     def islower(self):  # real signature unknown; restored from __doc__
         """
         S.islower() -> bool

         Return True if all cased characters in S are lowercase and there is
         at least one cased character in S, False otherwise.
         """
         return False
     # 判断字符串中字母是否都是小写，返回bool类型
     # >>> a
     # 'abel342'
     # >>> b = a.islower()
     # >>> b
     # True

     # >>> a = 'Abel83'
     # >>> b = a.islower()
     # >>> b
     # False

     def isnumeric(self):  # real signature unknown; restored from __doc__
         """
         S.isnumeric() -> bool

         Return True if there are only numeric characters in S,
         False otherwise.
         """
         return False
     # 判断字符串中是否都是数字，返回bool类型
     # >>> a = 'abel349'
     # >>> b = a.isnumeric()
     # >>> b
     # False
     # >>> a = '123'
     # >>> b = a.isnumeric()
     # >>> b
     # True
     def isprintable(self):  # real signature unknown; restored from __doc__
         """
         S.isprintable() -> bool

         Return True if all characters in S are considered
         printable in repr() or S is empty, False otherwise.
         """
         return False
     # 判断是不是只包含可打印字符，返回Bool值
     # >>> a
     # '天天向上\t2016'
     # >>> b = a.isprintable()
     # >>> b
     # False
     # >>> q = 'this is test'
     # >>> b = a.isprintable()
     # >>> b
     # False

     def isspace(self):  # real signature unknown; restored from __doc__
         """
         S.isspace() -> bool

         Return True if all characters in S are whitespace
         and there is at least one character in S, False otherwise.
         """
         return False
     # 判断是不是只包含空格字符，返回bool值

     def istitle(self):  # real signature unknown; restored from __doc__
         """
         S.istitle() -> bool

         Return True if S is a titlecased string and there is at least one
         character in S, i.e. upper- and titlecase characters may only
         follow uncased characters and lowercase characters only cased ones.
         Return False otherwise.
         """
         return False
     # 判断是不是每个词的首字母是不是大写，返回Bool值。一般标题会使用

     def isupper(self):  # real signature unknown; restored from __doc__
         """
         S.isupper() -> bool

         Return True if all cased characters in S are uppercase and there is
         at least one cased character in S, False otherwise.
         """
         return False
     # 判断字符串是不是都是大写，返回bool值

     def join(self, iterable):  # real signature unknown; restored from __doc__
         """
         S.join(iterable) -> str

         Return a string which is the concatenation of the strings in the
         iterable.  The separator between elements is S.
         """
         return ""
     # 返回通过指定字符分隔的新字符串
     # >>> a = ['a', 'b', 'c', 'f']
     # >>> b = "_".join(a)
     # >>> b
     # 'a_b_c_f'

     def ljust(self, width, fillchar=None):  # real signature unknown; restored from __doc__
         """
         S.ljust(width[, fillchar]) -> str

         Return S left-justified in a Unicode string of length width. Padding is
         done using the specified fill character (default is a space).
         """
         return ""
     # 左对齐，右添充，参数width 宽度(fillchar 添充字符，默认是空格)

     def lower(self):  # real signature unknown; restored from __doc__
         """
         S.lower() -> str

         Return a copy of the string S converted to lowercase.
         """
         return ""
     # 转换为小写

     def lstrip(self, chars=None):  # real signature unknown; restored from __doc__
         """
         S.lstrip([chars]) -> str

         Return a copy of the string S with leading whitespace removed.
         If chars is given and not None, remove characters in chars instead.
         """
         return ""
     # 删除左边的空白或自定义的字符
     # >>> a = "   Hi, I'm Abel"
     # >>> b = a.lstrip()
     # >>> b
     # "Hi, I'm Abel"
     def maketrans(self, *args, **kwargs):  # real signature unknown
         """
         Return a translation table usable for str.translate().

         If there is only one argument, it must be a dictionary mapping Unicode
         ordinals (integers) or characters to Unicode ordinals, strings or None.
         Character keys will be then converted to ordinals.
         If there are two arguments, they must be strings of equal length, and
         in the resulting dictionary, each character in x will be mapped to the
         character at the same position in y. If there is a third argument, it
         must be a string, whose characters will be mapped to None in the result.
         """
         pass
     # str.translate()函数配合使用，替换相应的字符

     def partition(self, sep):  # real signature unknown; restored from __doc__
         """
         S.partition(sep) -> (head, sep, tail)

         Search for the separator sep in S, and return the part before it,
         the separator itself, and the part after it.  If the separator is not
         found, return S and two empty strings.
         """
         pass
     # 用于拆分字符串，返回一个包含三个元素的元组;返回一个包含三个元素的元组。如果指定的字符串sep不存在，则返回自己加两个空元素。
     # >>> a = "Hi, I'm abel"
     # >>> b = a.partition('a')
     # >>> b
     # ("Hi, I'm ", 'a', 'bel')
     # >>> c = a.partition('z')
     # >>> c
     # ("Hi, I'm abel", '', '')
     def replace(self, old, new, count=None):  # real signature unknown; restored from __doc__
         """
         S.replace(old, new[, count]) -> str

         Return a copy of S with all occurrences of substring
         old replaced by new.  If the optional argument count is
         given, only the first count occurrences are replaced.
         """
         return ""
     # 使用新的字符串替换老的字符串(可选参数count 指定替换的次数，默认是全部)
     # >>> a = "Abelisgood"
     # >>> b = a.replace('o', 'z')
     # >>> b
     # 'Abelisgzzd'
     # >>> b = a.replace('o', 'z', 1)
     # >>> b
     # 'Abelisgzod'

     def rfind(self, sub, start=None, end=None):  # real signature unknown; restored from __doc__
         """
         S.rfind(sub[, start[, end]]) -> int

         Return the highest index in S where substring sub is found,
         such that sub is contained within S[start:end].  Optional
         arguments start and end are interpreted as in slice notation.

         Return -1 on failure.
         """
         return 0
     # 反向查找，与find 是相反方向        

     def rindex(self, sub, start=None, end=None):  # real signature unknown; restored from __doc__
         """
         S.rindex(sub[, start[, end]]) -> int

         Like S.rfind() but raise ValueError when the substring is not found.
         """
         return 0
     # 返回字符串所在的索引，与index 相反方向

     def rjust(self, width, fillchar=None):  # real signature unknown; restored from __doc__
         """
         S.rjust(width[, fillchar]) -> str

         Return S right-justified in a string of length width. Padding is
         done using the specified fill character (default is a space).
         """
         return ""
     # 右对齐，右填充。与ljust 相反

     def rpartition(self, sep):  # real signature unknown; restored from __doc__
         """
         S.rpartition(sep) -> (head, sep, tail)

         Search for the separator sep in S, starting at the end of S, and return
         the part before it, the separator itself, and the part after it.  If the
         separator is not found, return two empty strings and S.
         """
         pass
     # 拆分：与 partition相反，只不过是从字符串的右边开始拆分。
     def rsplit(self, sep=None, maxsplit=-1):  # real signature unknown; restored from __doc__
         """
         S.rsplit(sep=None, maxsplit=-1) -> list of strings

         Return a list of the words in S, using sep as the
         delimiter string, starting at the end of the string and
         working to the front.  If maxsplit is given, at most maxsplit
         splits are done. If sep is not specified, any whitespace string
         is a separator.
         """
         return []
     # 与split类似，从右边开始拆分，返回一个列表类型,（可选参数maxsplit 每次+- 1  sep 的值默认是空格）
     def rstrip(self, chars=None):  # real signature unknown; restored from __doc__
         """
         S.rstrip([chars]) -> str

         Return a copy of the string S with trailing whitespace removed.
         If chars is given and not None, remove characters in chars instead.
         """
         return ""
     # 

     def split(self, sep=None, maxsplit=-1):  # real signature unknown; restored from __doc__
         """
         S.split(sep=None, maxsplit=-1) -> list of strings

         Return a list of the words in S, using sep as the
         delimiter string.  If maxsplit is given, at most maxsplit
         splits are done. If sep is not specified or is None, any
         whitespace string is a separator and empty strings are
         removed from the result.
         """
         return []
     # 从左边开始拆分，返回一个列表类型,（可选参数maxsplit 每次+- 1  sep 的值默认是空格）

     def splitlines(self, keepends=None):  # real signature unknown; restored from __doc__
         """
         S.splitlines([keepends]) -> list of strings

         Return a list of the lines in S, breaking at line boundaries.
         Line breaks are not included in the resulting list unless keepends
         is given and true.
         """
         return []
     # 拆分多行字符串，以每行一个元素生成一个新的列表，如果是单行字符串，则返回原字符串

     def startswith(self, prefix, start=None, end=None):  # real signature unknown; restored from __doc__
         """
         S.startswith(prefix[, start[, end]]) -> bool

         Return True if S starts with the specified prefix, False otherwise.
         With optional start, test S beginning at that position.
         With optional end, stop comparing S at that position.
         prefix can also be a tuple of strings to try.
         """
         return False
     # 是否以字符串开始(可选参数，start与end 分别代表起始和结束),返回bool值

     def strip(self, chars=None):  # real signature unknown; restored from __doc__
         """
         S.strip([chars]) -> str

         Return a copy of the string S with leading and trailing
         whitespace removed.
         If chars is given and not None, remove characters in chars instead.
         """
         return ""
     # 去除左边空白或自定义字符串

     def swapcase(self):  # real signature unknown; restored from __doc__
         """
         S.swapcase() -> str

         Return a copy of S with uppercase characters converted to lowercase
         and vice versa.
         """
         return ""
     # 把字符串的大小写字母互换输出

     def title(self):  # real signature unknown; restored from __doc__
         """
         S.title() -> str

         Return a titlecased version of S, i.e. words start with title case
         characters, all remaining cased characters have lower case.
         """
         return ""
     # 字符串首字母大写，其他全部小写

     def translate(self, table):  # real signature unknown; restored from __doc__
         """
         S.translate(table) -> str

         Return a copy of the string S in which each character has been mapped
         through the given translation table. The table must implement
         lookup/indexing via __getitem__, for instance a dictionary or list,
         mapping Unicode ordinals to Unicode ordinals, strings, or None. If
         this operation raises LookupError, the character is left untouched.
         Characters mapped to None are deleted.
         """
         return ""
     # str.maketrans()函数配合使用，替换相应的字符

     def upper(self):  # real signature unknown; restored from __doc__
         """
         S.upper() -> str

         Return a copy of S converted to uppercase.
         """
         return ""
     # 与lower 相反，全部转换为大写

     def zfill(self, width):  # real signature unknown; restored from __doc__
         """
         S.zfill(width) -> str

         Pad a numeric string S with zeros on the left, to fill a field
         of the specified width. The string S is never truncated.
         """
         return ""
     # 回一个添充的字符串，width 添写长度，如果长宽和字符串相等，则直接返回字符串本身，如果长度大小字符串，则用0添充至指定的长度

     def __add__(self, *args, **kwargs):  # real signature unknown
         """ Return self+value. """
         pass

     def __contains__(self, *args, **kwargs):  # real signature unknown
         """ Return key in self. """
         pass

     # str中包含的key或者字节

     def __eq__(self, *args, **kwargs):  # real signature unknown
         """ Return self==value. """
         pass

     def __format__(self, format_spec):  # real signature unknown; restored from __doc__
         """
         S.__format__(format_spec) -> str

         Return a formatted version of S as described by format_spec.
         """
         return ""

     def __getattribute__(self, *args, **kwargs):  # real signature unknown
         """ Return getattr(self, name). """
         pass

     # 反射时候使用

     def __getitem__(self, *args, **kwargs):  # real signature unknown
         """ Return self[key]. """
         pass
     #

     def __getnewargs__(self, *args, **kwargs):  # real signature unknown
         pass

     def __ge__(self, *args, **kwargs):  # real signature unknown
         """ Return self>=value. """
         pass

     def __gt__(self, *args, **kwargs):  # real signature unknown
         """ Return self>value. """
         pass

     def __hash__(self, *args, **kwargs):  # real signature unknown
         """ Return hash(self). """
         pass

     def __init__(self, value='', encoding=None, errors='strict'):  # known special case of str.__init__
         """
         str(object='') -> str
         str(bytes_or_buffer[, encoding[, errors]]) -> str

         Create a new string object from the given object. If encoding or
         errors is specified, then the object must expose a data buffer
         that will be decoded using the given encoding and error handler.
         Otherwise, returns the result of object.__str__() (if defined)
         or repr(object).
         encoding defaults to sys.getdefaultencoding().
         errors defaults to 'strict'.
         # (copied from class doc)
         """
         pass

     def __iter__(self, *args, **kwargs):  # real signature unknown
         """ Implement iter(self). """
         pass

     def __len__(self, *args, **kwargs):  # real signature unknown
         """ Return len(self). """
         pass

     def __le__(self, *args, **kwargs):  # real signature unknown
         """ Return self<=value. """
         pass

     def __lt__(self, *args, **kwargs):  # real signature unknown
         """ Return self<value. """
         pass

     def __mod__(self, *args, **kwargs):  # real signature unknown
         """ Return self%value. """
         pass

     def __mul__(self, *args, **kwargs):  # real signature unknown
         """ Return self*value.n """
         pass

     @staticmethod  # known case of __new__
     def __new__(*args, **kwargs):  # real signature unknown
         """ Create and return a new object.  See help(type) for accurate signature. """
         pass

     def __ne__(self, *args, **kwargs):  # real signature unknown
         """ Return self!=value. """
         pass

     def __repr__(self, *args, **kwargs):  # real signature unknown
         """ Return repr(self). """
         pass

     def __rmod__(self, *args, **kwargs):  # real signature unknown
         """ Return value%self. """
         pass

     def __rmul__(self, *args, **kwargs):  # real signature unknown
         """ Return self*value. """
         pass

     def __sizeof__(self):  # real signature unknown; restored from __doc__
         """ S.__sizeof__() -> size of S in memory, in bytes """
         pass

     def __str__(self, *args, **kwargs):  # real signature unknown
         """ Return str(self). """
         pass