python——字符串与序列

字符串

python中没有字符的概念==与元组一样，不能直接修改

支持拼接版的修改

>>> str1='asdf'>>> str1.capitalize()'Asdf'>>> str1'asdf'>>> str1='DSADas'>>> str1.casefold()'dsadas'>>> str1'DSADas'>>> str1.center(40)'                 DSADas                 '>>> str1'DSADas'>>> str1.count('a')1>>> str1.count('a',true)Traceback (most recent call last):  File "<pyshell#9>", line 1, in <module>    str1.count('a',true)NameError: name 'true' is not defined>>> str1.endwith(('s')KeyboardInterrupt>>> str1.endswith('s')True>>> str1='i\tlove\tprogoram'>>> str1.expandtabs()'i       love    progoram'>>> str1.find('pro')7>>> str1.find('f')-1>>> str1.index('f')Traceback (most recent call last):  File "<pyshell#20>", line 1, in <module>    str1.index('f')ValueError: substring not found>>> str1.index('pro')7isalnum()=isalpha()+isdigit()>>> str2='周雨佳'>>> str2.islower()  至少包含一个区分大小写的字符，且这些字符都是小写，返回trueFalseistitle()所有单词首字母都是大写，其他字母都是小写isupper()所有字母都是大写>>> str2.join('dsds')'d周雨佳s周雨佳d周雨佳s'>>> str3=' fdsfsd   sfds  '>>> str3.lstrip()'fdsfsd   sfds  '>>> str3.rstrip()' fdsfsd   sfds'>>> str3.partition('ds')(' f', 'ds', 'fsd   sfds  ')>>> str3.replace('f','z',2)' zdszsd   sfds  'rfind rindex rstrip startswith strip一样的>>> str3.split('')Traceback (most recent call last):  File "<pyshell#30>", line 1, in <module>    str3.split('')ValueError: empty separator>>> str3.split()['fdsfsd', 'sfds']>>> str3' fdsfsd   sfds  '>>> str3.strip('s')' fdsfsd   sfds  '>>> str4='FFSDds'>>> str4.swap()Traceback (most recent call last):  File "<pyshell#35>", line 1, in <module>    str4.swap()AttributeError: 'str' object has no attribute 'swap'>>> str3.title()' Fdsfsd   Sfds  '>>> str3.translate(str.maketrans('s','z'))' fdzfzd   zfdz  '>>> str3.maketrans('s','z'){115: 122}>>> str3.zfill(30)'00000000000000 fdsfsd   sfds  '

格式化字符串

>>> str1='asdf'>>> str1.capitalize()'Asdf'>>> str1'asdf'>>> str1='DSADas'>>> str1.casefold()'dsadas'>>> str1'DSADas'>>> str1.center(40)'                 DSADas                 '>>> str1'DSADas'>>> str1.count('a')1>>> str1.count('a',true)Traceback (most recent call last):  File "<pyshell#9>", line 1, in <module>    str1.count('a',true)NameError: name 'true' is not defined>>> str1.endwith(('s')KeyboardInterrupt>>> str1.endswith('s')True>>> str1='i\tlove\tprogoram'>>> str1.expandtabs()'i       love    progoram'>>> str1.find('pro')7>>> str1.find('f')-1>>> str1.index('f')Traceback (most recent call last):  File "<pyshell#20>", line 1, in <module>    str1.index('f')ValueError: substring not found>>> str1.index('pro')7>>> str2='周雨佳'>>> str2.islower()False>>> str2.join('dsds')'d周雨佳s周雨佳d周雨佳s'>>> str3=' fdsfsd   sfds  '>>> str3.lstrip()'fdsfsd   sfds  '>>> str3.rstrip()' fdsfsd   sfds'>>> str3.partition('ds')(' f', 'ds', 'fsd   sfds  ')>>> str3.replace('f','z',2)' zdszsd   sfds  '>>> str3.split('')Traceback (most recent call last):  File "<pyshell#30>", line 1, in <module>    str3.split('')ValueError: empty separator>>> str3.split()['fdsfsd', 'sfds']>>> str3' fdsfsd   sfds  '>>> str3.strip('s')' fdsfsd   sfds  '>>> str4='FFSDds'>>> str4.swap()Traceback (most recent call last):  File "<pyshell#35>", line 1, in <module>    str4.swap()AttributeError: 'str' object has no attribute 'swap'>>> str3.title()' Fdsfsd   Sfds  '>>> str3.translate(str.maketrans('s','z'))' fdzfzd   zfdz  '>>> str3.maketrans('s','z'){115: 122}>>> str3.zfill(30)'00000000000000 fdsfsd   sfds  '>>> "{0} love{1}.{2}".format("i","am",'misszhou')'i loveam.misszhou'>>> "{a}{b}{c}".format(a="i",b="am",c="misszhou")'iammisszhou'>>> "{a}{b}{0}".format(a="i",b="am","misszhou")SyntaxError: positional argument follows keyword argument>>> print('\tz')z>>> "{{0}}".format("no")'{0}'>>> '{0:.lf}{1}'.format(27.2324,'GB')Traceback (most recent call last):  File "<pyshell#45>", line 1, in <module>    '{0:.lf}{1}'.format(27.2324,'GB')ValueError: Format specifier missing precision>>> '{0:.1f}{1}SyntaxError: EOL while scanning string literal>>> '{0:.1f}{1}'.format(27.2324,'GB')'27.2GB' %c %s %d o x  X f e E g G（根据数字大小选择f e)>>> '%c' %97'a'>>> '%c%c%c' % {97,98,99}Traceback (most recent call last):  File "<pyshell#49>", line 1, in <module>    '%c%c%c' % {97,98,99}TypeError: %c requires int or char>>> '%c%c%c' % (97,98,99)'abc'>>> '%s' % 'jkfjdk''jkfjdk'>>> '%d+%d=%d' % (4,5,4+5)'4+5=9'>>> '%o' % 12'14'>>> '%x' %10'a'>>> '%f" %23.43423SyntaxError: EOL while scanning string literal>>> '%f'%2343'2343.000000'>>> '%e'%342443r5r32SyntaxError: invalid syntax>>> '%e'%432434'4.324340e+05'格式化操作符辅助指令>>> '%10d'%5'         5'>>> '%-10d'%4'4         '>>> '%+d'%4'+4'>>> '%+d'%-5'-5'>>> '%#o'%432'0o660'>>> '%#X'%4543'0X11BF'>>> '%#d'%4342'4342'>>> '%010d'%4342'0000004342'>>> '%-010d'%43543'43543     '

转义字符也是一样用的

\t \n \r

序列

列表、元组、字符串的共同点

都可以通过索引得到每一个元素

默认索引值是0

可以通过分片的方法得到一个范围内的元素集合

有很多相同的操作符

list

>>> help(list)Help on class list in module builtins:class list(object) |  list() -> new empty list |  list(iterable) -> new list initialized from iterable's items |  （迭代：重复反馈过程的活动，目的通常是为了接近和达到所需的目标或结果，每次重复叫做迭代，每次迭代的结果作为下一次的初始值） |  Methods defined here: |   |  __add__(self, value, /) |      Return self+value. |   |  __contains__(self, key, /) |      Return key in self. |   |  __delitem__(self, key, /) |      Delete self[key]. |   |  __eq__(self, value, /) |      Return self==value. |   |  __ge__(self, value, /) |      Return self>=value. |   |  __getattribute__(self, name, /) |      Return getattr(self, name). |   |  __getitem__(...) |      x.__getitem__(y) <==> x[y] |   |  __gt__(self, value, /) |      Return self>value. |   |  __iadd__(self, value, /) |      Implement self+=value. |   |  __imul__(self, value, /) |      Implement self*=value. |   |  __init__(self, /, *args, **kwargs) |      Initialize self.  See help(type(self)) for accurate signature. |   |  __iter__(self, /) |      Implement iter(self). |   |  __le__(self, value, /) |      Return self<=value. |   |  __len__(self, /) |      Return len(self). |   |  __lt__(self, value, /) |      Return self<value. |   |  __mul__(self, value, /) |      Return self*value.n |   |  __ne__(self, value, /) |      Return self!=value. |   |  __new__(*args, **kwargs) from builtins.type |      Create and return a new object.  See help(type) for accurate signature. |   |  __repr__(self, /) |      Return repr(self). |   |  __reversed__(...) |      L.__reversed__() -- return a reverse iterator over the list |   |  __rmul__(self, value, /) |      Return self*value. |   |  __setitem__(self, key, value, /) |      Set self[key] to value. |   |  __sizeof__(...) |      L.__sizeof__() -- size of L in memory, in bytes |   |  append(...) |      L.append(object) -> None -- append object to end |   |  clear(...) |      L.clear() -> None -- remove all items from L |   |  copy(...) |      L.copy() -> list -- a shallow copy of L |   |  count(...) |      L.count(value) -> integer -- return number of occurrences of value |   |  extend(...) |      L.extend(iterable) -> None -- extend list by appending elements from the iterable |   |  index(...) |      L.index(value, [start, [stop]]) -> integer -- return first index of value. |      Raises ValueError if the value is not present. |   |  insert(...) |      L.insert(index, object) -- insert object before index |   |  pop(...) |      L.pop([index]) -> item -- remove and return item at index (default last). |      Raises IndexError if list is empty or index is out of range. |   |  remove(...) |      L.remove(value) -> None -- remove first occurrence of value. |      Raises ValueError if the value is not present. |   |  reverse(...) |      L.reverse() -- reverse *IN PLACE* |   |  sort(...) |      L.sort(key=None, reverse=False) -> None -- stable sort *IN PLACE* |   |  ---------------------------------------------------------------------- |  Data and other attributes defined here: |   |  __hash__ = None>>> a=list()>>> a[]>>> b='i am misszhou'>>> b=list(b)>>> b['i', ' ', 'a', 'm', ' ', 'm', 'i', 's', 's', 'z', 'h', 'o', 'u']>>> c=(1,1,3,5,8)>>> c=list(c)>>> c[1, 1, 3, 5, 8]>>> help(tuple)Help on class tuple in module builtins:class tuple(object) |  tuple() -> empty tuple |  tuple(iterable) -> tuple initialized from iterable's items |   |  If the argument is a tuple, the return value is the same object. |   |  Methods defined here: |   |  __add__(self, value, /) |      Return self+value. |   |  __contains__(self, key, /) |      Return key in self. |   |  __eq__(self, value, /) |      Return self==value. |   |  __ge__(self, value, /) |      Return self>=value. |   |  __getattribute__(self, name, /) |      Return getattr(self, name). |   |  __getitem__(self, key, /) |      Return self[key]. |   |  __getnewargs__(...) |   |  __gt__(self, value, /) |      Return self>value. |   |  __hash__(self, /) |      Return hash(self). |   |  __iter__(self, /) |      Implement iter(self). |   |  __le__(self, value, /) |      Return self<=value. |   |  __len__(self, /) |      Return len(self). |   |  __lt__(self, value, /) |      Return self<value. |   |  __mul__(self, value, /) |      Return self*value.n |   |  __ne__(self, value, /) |      Return self!=value. |   |  __new__(*args, **kwargs) from builtins.type |      Create and return a new object.  See help(type) for accurate signature. |   |  __repr__(self, /) |      Return repr(self). |   |  __rmul__(self, value, /) |      Return self*value. |   |  count(...) |      T.count(value) -> integer -- return number of occurrences of value |   |  index(...) |      T.index(value, [start, [stop]]) -> integer -- return first index of value. |      Raises ValueError if the value is not present.>>> len(a)0>>> len(c)5>>> c[1, 1, 3, 5, 8]>>> max(c)8>>> max(b)'z'>>> numbers=[1,18,13,0,-23,4,-342]>>> max(numbers)18>>> min(numbers)-342>>> chars='1232342'>>> min(chars)'1'>>> tuple1=(1,2,4,5,7,9)

必须是相同类型的才有max min 数字和字符不能比较