capitalize
data = 'hello'
print(data.capitalize())
结果
Hello
capitalize(self, /) ?首字母大写
? ? ? ?Return a capitalized version of the string.
? ? ? ?
? ? ? ?More specifically, make the first character have upper case and the rest lower
? ? ? ?case.
casefold
data = 'HELLO'
print(data.capitalize())
结果
Hello
? ?casefold(self, /) 全部换成小写
? ? ? ?Return a version of the string suitable for caseless comparisons.
? ?
center
print("age".center(10, '*')) # 居中对齐
print("20".center(10, '*'))
结果
***age****
****20****
? ?center(self, width, fillchar=' ', /) 居中对齐
? ? ? ?Return a centered string of length width.
? ? ? ?返回长度宽度居中的字符串。
? ? ? ?Padding is done using the specified fill character (default is a space).
? ? ? ?填充是使用指定的填充字符完成的（默认为空格）。
rjust
print("age".rjust(10, '*')) # 向右对齐
print("20".rjust(10, '*'))
结果
*******age
********20
? ? rjust(self, width, fillchar=' ', /) 右对齐
? ? ? ?Return a right-justified string of length width.
ljust
print("age".ljust(10, '*')) # 向左对齐
print("20".ljust(10, '*'))
结果
age*******
20********
?ljust(self, width, fillchar=' ', /) 左对齐
? ? ? ?Return a left-justified string of length width.
? ??
count
data = 'abcabcabc'
print(data.count('a'))
data = 'abcabcabc'
print(data.count('abc'))
结果
3
3
? ?count(...) 计数，统计字符或字符串的出现次数
? ? ? ?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.
?encode ?
data = 'abc'
print(data.encode('UTF-8'))
结果
b'abc'
? ?encode(self, /, encoding='utf-8', errors='strict')字符串编码字节
? ? ? ?Encode the string using the codec registered for encoding.
?
decode
data = b'abc'
print(data.decode('UTF-8'))
结果
abc
?decode 解码（字节解码成字符串）
? ? ? ?encoding
? ? ? ? ?The encoding in which to encode the string.
? ? ? ?errors
? ? ? ? ?The error handling scheme to use for encoding errors.
? ? ? ? ?The 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.
??
endswith
data = 'abcabcabc'
print(data.endswith('c'))
data = 'abcabcabc'
print(data.endswith('bc'))
data = 'abcabcabc'
print(data.endswith('abc'))
结果
True
True
True
? ? endswith(...) 判断以什么结尾（可以是字符串）
? ? ? ?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.
expandtabs? ?
data = 'abc\tabc'
print(data.expandtabs(tabsize=9))
结果
abc abc
? ?expandtabs(self, /, tabsize=8)扩展制表符没有限制
? ? ? ?Return a copy where all tab characters are expanded using spaces.
? ? ? ?
? ? ? ?If tabsize is not given, a tab size of 8 characters is assumed.
? ?
?find
data = 'abcabcabc'
print(data.find('b'))
结果
1
? ?find(...)返回最小的下标
? ? ? ?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.
? ?
name = 'zhangsan'
age = 30
money = 999999999
print("My name is {:*^10} My age is {:*^10} My money is {:*^13}".format(name, age, money))
结果
My name is *zhangsan* My age is ****30**** My money is **999999999**
? ?format(...)格式化（占位）
? ? ? ?S.format(*args, **kwargs) -> str
? ? ? ?
? ? ? ?Return a formatted version of S, using substitutions from args and kwargs.
? ? ? ?The substitutions are identified by braces ('{' and '}').
data = 'abcabc666'
data1 = 'abcd'
print(data1.format_map(data))
print(data1)
结果
abcd
abcd
? ?format_map(...) 使用data1格式化并替换data
? ? ? ?S.format_map(mapping) -> str
? ? ? ?
? ? ? ?Return a formatted version of S, using substitutions from mapping.
? ? ? ?The substitutions are identified by braces ('{' and '}').
? ?
index
data = 'abcabcdabcd'
print(data.index('a'))
结果
0
? ?index(...)返回 S 中找到子字符串子项的最低索引
? ?? ? ? ?
? ? ? ?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.
? ? ??
? ? ? ?Raises ValueError when the substring is not found.
? ?
?isalnum
data = 'abcabcdabcd123'
print(data.isalnum())
data = 'abcabcdabcd123-'
print(data.isalnum())
结果
True
False
? ?isalnum(self, /)如果字符串中只有字符或数字（或字母和数字），则返回 True，否则返回 False。
? ? ? ?Return True if the string is an alpha-numeric string, False otherwise.
? ? ? ?
? ? ? ?A string is alpha-numeric if all characters in the string are alpha-numeric and
? ? ? ?there is at least one character in the string.
? ?
?isalpha
data = 'abcabcdabcd123'
print(data.isalpha())
data = 'abcabcdabcd'
print(data.isalpha())
结果
False
True
? ?isalpha(self, /)如果字符串是字母字符串，则返回 True，否则返回 False。
? ? ? ?Return True if the string is an alphabetic string, False otherwise.
? ? ? ?
? ? ? ?A string is alphabetic if all characters in the string are alphabetic and there
? ? ? ?is at least one character in the string.
? ?
isascii
data = 'abcabcdabcd'
print(data.isascii())
data = '哈哈'
print(data.isascii())
结果
True
False
? ?isascii(self, /)如果字符串中的所有字符都是 ASCII码表中的，则返回 True，否则返回 False。
? ? ? ?Return True if all characters in the string are ASCII, False otherwise.
? ? ? ?
? ? ? ?ASCII characters have code points in the range U+0000-U+007F.
? ? ? ?Empty string is ASCII too.
? ?
isdecimal
data = 'x666'
print(data.isdecimal())
data = '666'
print(data.isdecimal())
结果
False
True
? ?isdecimal(self, /)如果字符串是十进制字符串，则返回 True，否则返回 False。
? ? ? ?Return True if the string is a decimal string, False otherwise.
? ? ? ?
? ? ? ?A string is a decimal string if all characters in the string are decimal and
? ? ? ?there is at least one character in the string.
? ?
?isdigit
data = '666'
print(data.isdigit())
data = '666abc'
print(data.isdigit())
结果
True
False
? ?isdigit(self, /)如果字符串是数字字符串，则返回 True，否则返回 False。
? ? ? ?Return True if the string is a digit string, False otherwise.
? ? ? ?
? ? ? ?A string is a digit string if all characters in the string are digits and there
? ? ? ?is at least one character in the string.
? ?
?isidentifier
data = '666abc'
print(data.isidentifier())
data = 'abc666'
print(data.isidentifier())
结果
False
True
? ?isidentifier(self, /)如果字符串是有效的 Python 标识符，则返回 True，否则返回 False。
? ? ? ?Return True if the string is a valid Python identifier, False otherwise.
? ? ? ?
? ? ? ?Call keyword.iskeyword(s) to test whether string s is a reserved identifier,
? ? ? ?such as "def" or "class".
? ?
*补充.python标识符?
Python标识符的命名规则
- Python 标识符由 26 个英文字母大小写，0-9 ，_ 组成。
- Python 标识符不能以数字开头。
- Python 标识符严格区分大小写。
- Python 标识符不能包含空格、@、% 以及 $ 等特殊字符。
- 不能以系统保留关键字作为标识符（一共有25 个）。
?islower
data = 'abc'
print(data.islower())
data = 'ABC'
print(data.islower())
结果
True
False
? islower(self, /)如果字符串是小写字符串，则返回 True，否则返回 False。
? ? ? ?Return True if the string is a lowercase string, False otherwise.
? ? ? ?
? ? ? ?A string is lowercase if all cased characters in the string are lowercase and
? ? ? ?there is at least one cased character in the string.
? ?
?isnumeric
data = '123'
print(data.isnumeric())
data = '123a'
print(data.isnumeric())
结果
True
False
? ?isnumeric(self, /)如果字符串是数字字符串，则返回 True，否则返回 False。
? ? ? ?Return True if the string is a numeric string, False otherwise.
? ? ? ?
? ? ? ?A string is numeric if all characters in the string are numeric and there is at
? ? ? ?least one character in the string.
? ?
isprintable
data = 'abc\nabc'
print(data.isprintable())
data = 'abcabc'
print(data.isprintable())
结果
False
True
? ?isprintable(self, /)如果字符串可打印，则返回 True，否则返回 False。
? ? ? ?Return True if the string is printable, False otherwise.
? ? ? ?
? ? ? ?A string is printable if all of its characters are considered printable in
? ? ? ?repr() or if it is empty.
? ?
isspace
data = ' '
print(data.isspace())
data = 'a'
print(data.isspace())
结果
True
False
? ?isspace(self, /)如果字符串是空格字符串，则返回 True，否则返回 False。
? ? ? ?Return True if the string is a whitespace string, False otherwise.
? ? ? ?
? ? ? ?A string is whitespace if all characters in the string are whitespace and there
? ? ? ?is at least one character in the string.
? ?
istitle
data = 'Money'
print(data.istitle())
data = 'MONEY'
print(data.istitle())
data = 'money'
print(data.istitle())
结果
True
False
False
? ?istitle(self, /)如果字符串是标题大小写的字符串，则返回 True，否则返回 False。
? ? ? ?Return True if the string is a title-cased string, False otherwise.
? ? ? ?
? ? ? ?In a title-cased string, upper- and title-case characters may only
? ? ? ?follow uncased characters and lowercase characters only cased ones.
?isupper?
data = 'ABC'
print(data.isupper())
data = 'abc'
print(data.isupper())
结果
True
False
? ?isupper(self, /)如果字符串是大写字符串，则返回 True，否则返回 False。
? ? ? ?Return True if the string is an uppercase string, False otherwise.
? ? ? ?
? ? ? ?A string is uppercase if all cased characters in the string are uppercase and
? ? ? ?there is at least one cased character in the string.
? ?
?join
print('-'.join(['bc', 'de']))
结果
bc-de
? ?Example: '.'.join(['ab', 'pq', 'rs']) -> 'ab.pq.rs'
? join(self, iterable, /)连接任意数量的字符串。
? ? ? ?Concatenate any number of strings.
? ? ? ?
? ? ? ?The string whose method is called is inserted in between each given string.
? ? ? ?The result is returned as a new string.
? ? ? ?
? ? ? ?
? ?
? ? ? ?
? ? ? ?Padding is done using the specified fill character (default is a space).
? ?
?lower
data = 'ABC'
print(data.lower())
结果
abc
? ?lower(self, /)返回转换为小写的字符串的副本。
? ? ? ?Return a copy of the string converted to lowercase.
? ?
lstrip
data = ' abc'
print(data.lstrip(), data)
结果
abc abc
? ?lstrip(self, chars=None, /)返回删除了前导空格的字符串副本。
? ? ? ?Return a copy of the string with leading whitespace removed.
? ? ? ?
? ? ? ?If chars is given and not None, remove characters in chars instead.
? ?
partition
data = 'ab|cd'
print((data.partition('|')))
结果
('ab', '|', 'cd')
? ?partition(self, sep, /)使用给定的分隔符将字符串划分为三个部分。
? ? ? ?Partition the string into three parts using the given separator.
? ? ? ?
? ? ? ?This will search for the separator in the string. ?If the separator is found,
? ? ? ?returns a 3-tuple containing the part before the separator, the separator
? ? ? ?itself, and the part after it.这将在字符串中搜索分隔符。?如果找到分隔符，
???????返回一个 3 元组，其中包含分隔符（分隔符）之前的部分
???????本身，以及它之后的部分。
? ? ? ?
? ? ? ?If the separator is not found, returns a 3-tuple containing the original string
? ? ? ?and two empty strings.如果未找到分隔符，则返回包含原始字符串的 3 元组
???????和两个空字符串。
? ?
removeprefix
data = 'abc'
print(data.removeprefix('a'))
data = 'abc'
print(data.removeprefix('ab'))
结果
bc
c
? ?removeprefix(self, prefix, /)返回一个删除了给定前缀字符串（如果存在）的 str。
? ? ? ?Return a str with the given prefix string removed if present.
? ? ? ?
? ? ? ?If the string starts with the prefix string, return string[len(prefix):].
? ? ? ?Otherwise, return a copy of the original string.
? ?
removesuffix
data = 'abc'
print(data.removesuffix('c'))
data = 'abc'
print(data.removesuffix('bc'))
结果
ab
a
? ?removesuffix(self, suffix, /)返回一个 str，如果存在，则删除给定的后缀字符串。
? ? ? ?Return a str with the given suffix string removed if present.
? ? ? ?
? ? ? ?If the string ends with the suffix string and that suffix is not empty,
? ? ? ?return string[:-len(suffix)]. Otherwise, return a copy of the original
? ? ? ?string.如果字符串以后缀字符串结尾，并且该后缀不为空，
???????返回字符串[：-len（后缀）]。否则，请返回原件的副本
???????字符串。
? ?
replace
data = 'abc'
print(data.replace('c', 'r'))
结果
abr
? ?replace(self, old, new, count=-1, /)返回一个副本，其中包含所有出现的旧子字符串，该子字符串已替换为 new。（默认替换所有匹配到的）
? ? ? ?Return a copy with all occurrences of substring old replaced by new.
? ? ? ?
? ? ? ? ?count
? ? ? ? ? Maximum number of occurrences to replace.
? ? ? ? ? -1 (the default value) means replace all occurrences.
? ? ??
? ? ? If the optional argument count is given, only the first count occurrences are
? ? ? ?replaced.
? ?
rfind
data = 'abcabc'
print(data.rfind('a'))
结果
3
? ?rfind(...)返回 S 中找到子字符串子项的最高索引，使得 sub 包含在 S[start：end] 中
? ? ? ?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.
? ?
rindex
data = 'abcabca'
print(data.rindex('a'))
结果
6
? ?rindex(...)
? ? ? ?S.rindex(sub[, start[, end]]) -> int 返回 S 中找到子字符串子项的最高索引，
? ? ? ?
? ? ? ?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.
? ? ? ?
? ? ? ?Raises ValueError when the substring is not found.
? ?
? ? ? ?
? ? ? ?Padding is done using the specified fill character (default is a space).
? ?
rpartition
data = 'a|c'
print(data.rpartition('|'))
结果
('a', '|', 'c')
? ?rpartition(self, sep, /)使用给定的分隔符将字符串划分为三个部分。
? ? ? ?Partition the string into three parts using the given separator.
? ? ? ?
? ? ? ?This will search for the separator in the string, starting at the end. If
? ? ? ?the separator is found, returns a 3-tuple containing the part before the
? ? ? ?separator, the separator itself, and the part after it.
? ? ? ?
? ? ? ?If the separator is not found, returns a 3-tuple containing two empty strings
? ? ? ?and the original string.
?
rsplit
?
data = 'a|c'
print(data.rsplit(sep='|'))
结果
['a', 'c']
? ?rsplit(self, /, sep=None, maxsplit=-1)返回字符串中单词的列表，使用 sep 作为分隔符字符串。
? ? ? ?Return a list of the words in the string, using sep as the delimiter string.
? ? ? ?
? ? ? ? ?sep
? ? ? ? ? ?The delimiter according which to split the string.
? ? ? ? ? ?None (the default value) means split according to any whitespace,
? ? ? ? ? ?and discard empty strings from the result.
? ? ? ? ?maxsplit
? ? ? ? ? ?Maximum number of splits to do.
? ? ? ? ? ?-1 (the default value) means no limit.
? ? ? ?
? ? ? ?Splits are done starting at the end of the string and working to the front. | ?
? ?rstrip(self, chars=None, /)
? ? ? ?Return a copy of the string with trailing whitespace removed.
? ? ? ?
? ? ? ?If chars is given and not None, remove characters in chars instead.
? ?
split
data = 'abc'
print(data.split(sep='b'))
结果
['a', 'c']
? ?split(self, /, sep=None, maxsplit=-1)返回字符串中单词的列表，使用 sep 作为分隔符字符串。
? ? ? ?Return a list of the words in the string, using sep as the delimiter string.
? ? ? ?
? ? ? ?sep
? ? ? ? ?The delimiter according which to split the string.
? ? ? ? ?None (the default value) means split according to any whitespace,
? ? ? ? ?and discard empty strings from the result.
? ? ? ?maxsplit
? ? ? ? ?Maximum number of splits to do.
? ? ? ? ?-1 (the default value) means no limit.
? ?
splitlines
data = 'abc\nabc'
print(data.splitlines())
结果
['abc', 'abc']
? ?splitlines(self, /, keepends=False)
? ? ? ?Return a list of the lines in the string, breaking at line boundaries.
? ? ? ?返回字符串中在行边界处断开的行的列表。
? ? ? ?Line breaks are not included in the resulting list unless keepends is given and
? ? ? ?true.
? ?
startswith
data = 'abc'
print(data.startswith('a'))
data = 'abc'
print(data.startswith('b'))
结果
True
False
? ?startswith(...)
? ? ? ?S.startswith(prefix[, start[, end]]) -> bool
? ? ? ?
? ? ? ?Return True if S starts with the specified prefix, False otherwise.
? ? ? ?如果 S 以指定的前缀开头，则返回 True，否则返回 False。
? ? ? ?With optional start, test S beginning at that position.
? ? ? ??使用可选的开始，测试 S 从该位置开始。
? ? ? ?With optional end, stop comparing S at that position.
? ? ? ?使用可选端，停止在该位置比较 S。?
? ? ? ?prefix can also be a tuple of strings to try.
? ? ? ?前缀也可以是要尝试的字符串元组。
?strip
data = ' abc '
print(data.strip())
print(data)
结果
abc
abc
? ?strip(self, chars=None, /)返回删除了前导和尾随空格的字符串副本。（删除前后空格）
? ? ? ?Return a copy of the string with leading and trailing whitespace removed.
? ? ? ?
? ? ? ?If chars is given and not None, remove characters in chars instead.
? ?
?swapcase
data = 'abcABC'
print(data.swapcase())
结果
ABCabc
? ?swapcase(self, /)将大写字符转换为小写，将小写字符转换为大写。
? ? ? ?Convert uppercase characters to lowercase and lowercase characters to uppercase.
? ?
title
data = 'ABCabc'
print(data.title())
结果
Abcabc
? ?title(self, /)返回字符串的一个版本，其中每个单词的标题都大写。(首字母大写，其余小写)
? ? ? ?Return a version of the string where each word is titlecased.
? ? ? ?
? ? ? ?More specifically, words start with uppercased characters and all remaining
? ? ? ?cased characters have lower case.更具体地说，单词以大写字符开头，其余所有字符都? ? ? ? ?以大写字母开头，大小写字符具有小写。
? ?
translate
data = 'abcabc'
print(data.translate({ord('a'): 'A'}))
结果
AbcAbc
转换为Unicode方法
? ? ?ord()
Example:ord('a')->就可以提取'a'的Unicode码
? ?translate(self, table, /)使用给定的翻译表替换字符串中的每个字符。
? ? ? ?Replace each character in the string using the given translation table.
? ? ? ?
? ? ? ? ?table
? ? ? ? ? ?Translation table, which must be a mapping of Unicode ordinals to
? ? ? ? ? ?Unicode ordinals, strings, or None.转换表，它必须是 Unicode 序数到
???????????Unicode 序号、字符串或无。
? ? ? ?
? ? ? ?The table must implement lookup/indexing via __getitem__, for instance a
? ? ? ?dictionary or list. ?If this operation raises LookupError, the character is
? ? ? ?left untouched. ?Characters mapped to None are deleted.
? ?
upper
data = 'abcAbc'
print(data.upper())
结果
ABCABC
? ?upper(self, /)返回转换为大写的字符串的副本。
? ? ? ?Return a copy of the string converted to uppercase.
? ?
zfill
data = 'abc'
print(data.zfill(10))
结果
0000000abc
? ?zfill(self, width, /)在左侧用零填充数字字符串，以填充给定宽度的字段。
? ? ? ?Pad a numeric string with zeros on the left, to fill a field of the given width.
? ? ? ?
? ? ? ?The string is never truncated.