字符工厂函数str()
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__ """ 首字母变大写 S.capitalize() -> str Return a capitalized version of S, i.e. make the first character have upper case and the rest lower case. """ return "" def casefold(self): # real signature unknown; restored from __doc__ """ S.casefold() -> str Return a version of S suitable for caseless comparisons. """ return "" def center(self, width, fillchar=None): # real signature unknown; restored from __doc__ """ 原来字符居中，不够用空格补全 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 "" def count(self, sub, start=None, end=None): # real signature unknown; restored from __doc__ """ 从一个范围内的统计某str出现次数 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 def encode(self, encoding='utf-8', errors='strict'): # real signature unknown; restored from __doc__ """ encode(encoding='utf-8',errors='strict') 以encoding指定编码格式编码，如果出错默认报一个ValueError，除非errors指定的是 ignore或replace 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"" 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 def expandtabs(self, tabsize=8): # real signature unknown; restored from __doc__ """ 将字符串中包含的 转换成tabsize个空格 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 "" 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 def format(self, *args, **kwargs): # known special case of str.format """ 格式化输出 三种形式： 形式一. >>> print('{0}{1}{0}'.format('a','b')) aba 形式二：（必须一一对应） >>> print('{}{}{}'.format('a','b')) Traceback (most recent call last): File "<input>", line 1, in <module> IndexError: tuple index out of range >>> print('{}{}'.format('a','b')) ab 形式三： >>> print('{name} {age}'.format(age=12,name='lhf')) lhf 12 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 def format_map(self, mapping): # real signature unknown; restored from __doc__ """ 与format区别 '{name}'.format(**dict(name='alex')) '{name}'.format_map(dict(name='alex')) 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 def isalnum(self): # real signature unknown; restored from __doc__ """ 至少一个字符，且都是字母或数字才返回True 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 def isalpha(self): # real signature unknown; restored from __doc__ """ 至少一个字符，且都是字母才返回True 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 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 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 def isidentifier(self): # real signature unknown; restored from __doc__ """ 字符串为关键字返回True 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 def islower(self): # real signature unknown; restored from __doc__ """ 至少一个字符，且都是小写字母才返回True 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 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 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 def isspace(self): # real signature unknown; restored from __doc__ """ 至少一个字符，且都是空格才返回True 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 def istitle(self): # real signature unknown; restored from __doc__ """ >>> a='Hello' >>> a.istitle() True >>> a='HellP' >>> a.istitle() False 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 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 def join(self, iterable): # real signature unknown; restored from __doc__ """ #对序列进行操作（分别使用' '与':'作为分隔符） >>> seq1 = ['hello','good','boy','doiido'] >>> print ' '.join(seq1) hello good boy doiido >>> print ':'.join(seq1) hello:good:boy:doiido #对字符串进行操作 >>> seq2 = "hello good boy doiido" >>> print ':'.join(seq2) h:e:l:l:o: :g:o:o:d: :b:o:y: :d:o:i:i:d:o #对元组进行操作 >>> seq3 = ('hello','good','boy','doiido') >>> print ':'.join(seq3) hello:good:boy:doiido #对字典进行操作 >>> seq4 = {'hello':1,'good':2,'boy':3,'doiido':4} >>> print ':'.join(seq4) boy:good:doiido:hello #合并目录 >>> import os >>> os.path.join('/hello/','good/boy/','doiido') '/hello/good/boy/doiido' S.join(iterable) -> str Return a string which is the concatenation of the strings in the iterable. The separator between elements is S. """ return "" 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 "" def lower(self): # real signature unknown; restored from __doc__ """ S.lower() -> str Return a copy of the string S converted to lowercase. """ return "" 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 "" 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 def partition(self, sep): # real signature unknown; restored from __doc__ """ 以sep为分割，将S分成head,sep,tail三部分 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 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 "" 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 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 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 "" 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 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 [] 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__ """ 以sep为分割，将S切分成列表，与partition的区别在于切分结果不包含sep， 如果一个字符串中包含多个sep那么maxsplit为最多切分成几部分 >>> a='a,b c d e' >>> a.split() ['a,b', 'c', 'd', 'e'] 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 [] def splitlines(self, keepends=None): # real signature unknown; restored from __doc__ """ Python splitlines() 按照行(' ', ' ', ')分隔， 返回一个包含各行作为元素的列表，如果参数 keepends 为 False，不包含换行符，如 果为 True，则保留换行符。 >>> x 'adsfasdf sadf asdf adf' >>> x.splitlines() ['adsfasdf', 'sadf', 'asdf', 'adf'] >>> x.splitlines(True) ['adsfasdf ', 'sadf ', 'asdf ', 'adf'] 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 [] 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 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 "" def swapcase(self): # real signature unknown; restored from __doc__ """ 大小写反转 S.swapcase() -> str Return a copy of S with uppercase characters converted to lowercase and vice versa. """ return "" 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 "" def translate(self, table): # real signature unknown; restored from __doc__ """ table=str.maketrans('alex','big SB') a='hello abc' print(a.translate(table)) 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 "" def upper(self): # real signature unknown; restored from __doc__ """ S.upper() -> str Return a copy of S converted to uppercase. """ return "" def zfill(self, width): # real signature unknown; restored from __doc__ """ 原来字符右对齐，不够用0补齐 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 "" 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 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 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 字符串工厂函数 字符串工厂函数
1 msg="hello world" 2 3 print(msg.capitalize()) #首字母变大写 4 #Hello world 5 6 print(msg.center(20,'*')) #原来字符居中，不够用*补全 7 #****hello world***** 8 9 print(msg.count('l')) #从一个范围内的统计某str出现次数 10 #3 11 12 print(msg[4]) #输出第4位索引，第一位索引为0 13 #o 14 15 print(msg.count('l',3,10)) #统计3位索引到第十位索引l出现的次数 16 #2 17 18 print(msg.count('l',3,-1)) #统计3位索引到倒数第一位索引‘l’出现的次数 19 #2 20 21 print(msg.endswith('d')) #查看随后一位是否为‘d’ 22 #True
msg1="a b" print(msg1.expandtabs(10)) #将字符串中包含的 转换成tabsize个空格 #a b print(msg1.find("z")) #查找字符串中是否含有“z”元素，没有则返回-1 #-1 print('{0} {1}'.format('name','age') ) #格式化输出 #name age print('{0} {1} {0}'.format('name','age') ) #name age name print('{name}'.format(name='mo')) #mo print('{} {}'.format('name','age') ) #name age print(msg1.index("b")) #找到索引的位置 #2
1 msg3='a123' 2 print(msg3.isalnum()) #至少一个字符，且都是字母或数字才返回True 3 #True 4 5 msg3='a123_' 6 print(msg3.isalnum()) 7 #False 8 9 msg3='aKJ' 10 print(msg3.isalnum()) 11 #True 12 13 msg3='12Ajd' 14 print(msg3.isalpha()) #至少一个字符，且都是字母才返回True 15 #False 16 17 msg5='10.5' 18 print(msg5.isdecimal()) #如果在s中只有十进制字符，则返回真，否则为假 19 #False 20 21 msg6='10' 22 print(msg6.isdigit()) #如果在s中的所有字符都是数字，则返回真 23 #True 24 25 msg7='10.3' 26 print(msg7.isnumeric()) #如果在s中只有数字字符，则返回真值 27 #False 28 29 msg8='if' 30 print(msg8.isidentifier()) #字符串为关键字返回True 31 #True 32 33 msg9='aaa' 34 print(msg9.islower()) #至少一个字符，且都是小写字母才返回True 35 #True 36 37 msg10=' ' 38 print(msg10.isspace()) #至少一个字符，且都是空格才返回True 39 #True 40 41 msg11='Hello' 42 print(msg11.istitle()) #单词的第一个字母大写 43 #True 44 45 msg11='HelloWorld' 46 print(msg11.istitle()) 47 #False 48 49 msg12='AAD' 50 print(msg12.isupper()) #至少一个字符，且都是大写字母才返回True 51 #True 52 53 msg13='abc' 54 print(msg13.ljust(10,'*')) #返回左在一个长宽Unicode字符串对齐。填充的是使用指定的填充字符（默认是一个空格) 55 #abc******* 56 57 print(msg13.rjust(10,'*')) 58 #*******abc 59 60 msg15=' jlsdkj ' 61 print(msg15.strip()) #去掉字符串的空格 62 #jlsdkj 63 64 print(msg15.rstrip()) #去掉右空格 65 # jlsdkj 66 67 print(msg15.lstrip()) #去掉左空格 68 #jlsdkj 69 70 msg16='my name is abcd' 71 table=str.maketrans('a','A') 72 print(msg16.translate(table)) #x中的每一个字符都将被映射到在Y的同一位置的字符 73 #my nAme is Abcd 74 75 msg17='abc' 76 print(msg17.zfill(20)) #原来字符右对齐，不够用0补齐 77 #00000000000000000abc
常用的：
1 msg19=' 21klsjf ' #去空白 2 print(msg19.strip()) 3 #21klsjf 4 5 6 msg20='nihao 123' #切片，顾头不顾尾 7 print(msg20[0:3]) 8 #nih 9 10 print(msg20[0:]) 11 #nihao 123 12 13 print(msg20[:]) 14 #nihao 123 15 16 print(msg20[0:-1]) 17 #nihao 12 18 19 print(msg20[2:7:2]) #取步长，2到7之间每两个取一个 20 #ho1