澳门威斯尼人平台登录str字符串 casefold( ) 方法

描述

find(卡塔尔(英语:State of Qatar) 方法检查评定字符串中是不是含有子字符串 str ,纵然内定 beg(开头) 和
end(截至)
范围,则检查是否带有在钦命范围内,要是钦赐范围内假若带有内定索引值,再次来到的是索引值在字符串中的开首地方。若是不包括索引值,重返-1。

str字符串常用方法,str字符串

Python字符串str的法子运用,python字符串str

#!usr/bin/env python
# -*-coding:utf-8-*-
#字符串通常用双引号或单引号来表示:'123',"abc","字符串"
#str字符串的常用方法有以下:字符串可以用于赋值临时变量s
#友情提示以下全是python2.x版本演示,python3.x请在print(放入测试打印),例如:print(len(s))
from string import maketrans
s3 = '123'
s2 = '   '
s1 = 'This Is \t Cash'
s='abcdefghijklmnopqrstuvwxyz'
s4 = "0000000this is string example....wow!!!0000000"
s5 = 'ab c\n\nde fg\rkl\r\n'
print s[0:6]    #切片,截取字符串中的一段(以下标的起始位置到结束位置)
print len(s)    #统计字符串的长度
print s.ljust(50,'0'),'--->ljust方法'   #返回一个原字符串右用字符串0填充左对齐并宽度50的新字符串
print s.rjust(50,'0'),'--->rjust方法'   #返回一个原字符串左用字符串0填充右对齐并宽度50的新字符串
print s.capitalize(),'--->capitalize方法'    #返回字符串首字母大写的副本
print s.center(50,'*'),'--->center方法'  #表示原字符串居中两边填充宽度的用法
print format(s, '.3'),'--->format方法'   #格式化输出也可当切片用的方式
print s.upper(),'--->upper方法' #将小写字母转换成大写字母
print s.lower(),'--->lower方法' #将大写字母转换成小写字母
print s3.isdigit(),'--->isdigit方法'   #判断字符串如果是数字返回真True,不是返回假False
print s.startswith('abc'),'--->startswith方法'   #判断字符串是否是以abc开头如果是返回真,否则返回假
print s.endswith('zz'),'--->endswith方法'  #判断字符串是否以yz结尾是返回真,否则返回假
print s1.expandtabs(),'--->expandtabs方法'   #把字符串中的 tab 符号('\t')转为空格,tab 符号('\t')默认的空格数是8
print s.isalnum(),'--->isalnum方法'   #判断字符串至少有一个字符并且所有字符都是字母或数字则返回 True,否则返回 False
print s.isalpha(),'--->isalpha方法'   #判断字符串至少有一个字符并且所有字符都是字母则返回 True,否则返回 False
print s2.isspace(),'--->isspace方法'  #判断字符串中只包含空格,则返回 True,否则返回 False
print s1.istitle(),'--->istitle方法'   #如果字符串中所有的单词拼写首字母是否为大写,且其他字母为小写则返回 True,否则返回 False
print s4.strip("0"),'--->strip方法' #返回移除字符串头尾指定的字符生成的新字符串
print s.find('sd'),'--->find方法'   #检查是否包含在指定范围内,如果包含子字符串返回开始的索引值,否则返回-1。
print s.index('s'),'--->index方法'  #检查是否包含在指定范围内,该方法与find()方法一样,只不过如果不在字符串中会报一个异常
print s.partition("k"),'--->partition方法'  #生成一个分隔符k,第一个为分隔符左边的子串,第二个为分隔符本身,第三个为分隔符右边的子串。
print s1.swapcase(),'--->swapcase方法' #返回大小写字母转换后生成的新字符串
print s5.splitlines(),'--->splitlines方法'   #返回一个包含各行作为元素的列表
print s2.join(s3),'--->join方法'   #返回通过指定字符连接序列中元素后生成的新字符串
print s3.translate(maketrans(s3,s2)) #返回翻译后的字符串(有点复杂)自信百度补脑
print s3.zfill(10),'--->zfill方法'  #返回指定宽度的字符串原字符串右对齐,前面填充0
#以下打印输出:

澳门威斯尼人平台登录 1

#!usr/bin/env python # -*-coding:utf-8-*-
#字符串平时用双引号或单引号来表示:’123′,”abc”,”字符串”
#str字符串…

描述

Python
casefold(卡塔尔(英语:State of Qatar)方法是Python3.3版本之后引入的,其遵循和 lower() 方法丰裕相像,都得以调换字符串中全体大写字符为小写。

二者的差异是:lower(卡塔尔(英语:State of Qatar)方法只对ASCII编码,也便是‘A-Z’有效,对于别的语言(非汉语或英语)中把大写转变为小写的动静只可以用
casefold(卡塔尔(قطر‎ 方法。

1.简练利用

字符串类型格式化选取format(卡塔尔国方法,基本选用格式是:

     <模板字符串>.format(<逗号分隔的参数>卡塔尔

调用format(卡塔尔(قطر‎方法后会重回三个新的字符串,参数从0 带头编号。

"{}:计算机{}的CPU 占用率为{}%。".format("2016-12-31","PYTHON",10)
Out[10]: '2016-12-31:计算机PYTHON的CPU 占用率为10%。'

 

format(卡塔尔国方法能够十二分有益地连接区别类别的变量或内容,要是须求输出大括号,选拔{{表示{,}}表示},举例:

"{}{}{}".format("圆周率是",3.1415926,"...")
Out[11]: '圆周率是3.1415926...'

"圆周率{{{1}{2}}}是{0}".format("无理数",3.1415926,"...")
Out[12]: '圆周率{3.1415926...}是无理数'

s="圆周率{{{1}{2}}}是{0}" #大括号本身是字符串的一部分

s
Out[14]: '圆周率{{{1}{2}}}是{0}'

s.format("无理数",3.1415926,"...") #当调用format()时解析大括号
Out[15]: '圆周率{3.1415926...}是无理数'

 

语法

find(卡塔尔(قطر‎方意大利语法:

str.find(str, beg=0, end=len(string))

 

    字符串是编制程序中常用的类型,字符型在内部存储器中是以单个情势积存的,举例name

“alex”,在内存中蕴藏的样式为[“a”,”l”,”e”,”x”],因而我们能够运用列表的许多作用来操作字符串,因为本身早先的时候一向在想怎么字符串能够采纳切成块,能够有目录,初始的时候一贯不晓得,后来掌握了Python字符串的积存情势之后才精通怎么存在此些主意。上面我们来探视字符串类型中蕴藏那多少个方法:

   
在Python中稍稍措施上边有注释,那是因为那些主意运用Python本身编排的,大家知晓Python中超级多是平素调用C语言中的方法,看不到的那个是C语言中的方法。

    1.capitalize(self)

    def capitalize(self): # real signature unknown; restored from
__doc__
    ”””
    S.capitalize() -> str
        首字母大写,只是第一个位居第一位第叁个首字母大写
    Return a capitalized version of S, i.e. make the first
character
    have upper case and the rest lower case.
    ”””
    return “”

   
capitalize(self卡塔尔(英语:State of Qatar)是位居第1位首字母大写,大家驾驭还应该有贰个办法title(卡塔尔(قطر‎,上边来相比那多少个办法的区别点:

    >>> name = “alex is sb”
  >>> name.capitalize()
  ’Alex is sb’
  >>> name.title()
  ’Alex Is Sb’

   
从上边能够观望,capitalize(self卡塔尔(英语:State of Qatar)是位居第2位首字母大写,其余字母比十分小写;而title(self卡塔尔方法是富有单词的首字母都大写,那一个在用的时候要明了是必要那么字母大写。

    2.casefold(self)

    def casefold(self): # real signature unknown; restored from
__doc__
    ”””
    S.casefold() -> str
        全数首字母小写,等价于lower(卡塔尔(英语:State of Qatar)
    Return a version of S suitable for caseless comparisons.
    ”””
    return “”

    casefold(self卡塔尔国是将大写字母转变为小写,等价于lower(self卡塔尔(英语:State of Qatar),实比如下:

    >>> name = “ALEX Is SB”
  >>> name.casefold()
  ’alex is sb’
  >>> name
  ’ALEX Is SB’
  >>> name.lower()
  ’alex is sb’

  3.center(self,width,fillchar=None)

    def center(self, width, fillchar=None): # real signature unknown;
restored from __doc__
    ”””
    S.center(width[, fillchar]) -> str
       
“””center(self,width,fillchar=None卡塔尔国是将字符串放到中间,两侧加上大肆符号,暗中认可空格”””
    Return S centered in a string of length width. Padding is
    done using the specified fill character (default is a space)
    ”””
    return “”

   
center(self,width,fillchar=None卡塔尔国,美化格式,把self放到中间,钦命放肆长度的字符,空白处用字符填充,默许时间和空间字符。示举个例子下:

    >>> name = “您好”
  >>> name.center(12)
  ’     您好     ‘
  >>> name.center(12,”-“)
  ’—–您好—–‘

    4.__format__(self,format_spec)

    def __format__(self, format_spec): # real signature unknown;
restored from __doc__
    ”””
    S.__format__(format_spec) -> str
        字符串的格式化
    Return a formatted version of S as described by format_spec.
    ”””
    return “”

   
__format__(self,format_spec卡塔尔字符串进行格式化,根据我们渴求的格式进行字符串格式化操作。详细可参看()

    >>> tp1 = “My name is {0},and I am {1} years old,I am
{2}”

  >>> tp1.format(“Alex”,”18″,”sb”)

    ‘My name is Alex,and I am 18 years old,I am sb’

    >>> tp2 = “I am {1} years old,my name is {2},and I am
{0}.”

  >>> tp2.format(“sb”,”18″,”Alex”)
  ’I am 18 years old,my name is Alex,and I am sb.’
   
这种形式也得以用在字符串的拼接上面,使用字符串的format(卡塔尔方法,在{}大括号中定义索引,告诉Python把哪些值传给索引地方。

    5.__getattribute__(self,*args,**kwargs)

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

        “””反射的时候用的”””
    pass

    6.__getitem__(self,*args,**kwargs)

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

    ”””得到字符串低端个要素,等价于self[key]”””
    pass  

   
正是收获字符串中第多少个地方的字符,大家知晓字符串在内部存储器中是以列表方式积累的,因而得以使用索引来获取单个字符,实比方下:

    >>> name = “Alexissb”
  >>> name.__getitem__(2)
  ’e’
  >>> name[2]
  ’e’
    字符串中索引是从0以前的,获取字符串中第多少个职分的字符。

    7.__getnewargs__(self,*args,**kwargs)

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

    ”””__getnewargs__是跟参数有关的”””
    pass

    8.__hash__(self,*args,**kwargs)

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

    9.__iter__(self,*args,**kwargs)

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

澳门威斯尼人平台登录 ,    10.__len__(self,*args,**kwargs)

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

        “””再次回到字符串的长短,等价与len(self卡塔尔(قطر‎”””
    pass

    实比如下:

    >>> name = “Alexissb”
  >>> name.__len__()
  8
  >>> len(name)
  8
    11.count(self,sub,start=None,end=None)
    def count(self, sub, start=None, end=None): # real signature
unknown; restored from __doc__
    ”””
    S.count(sub[, start[, end]]) -> int

        重返在字符串中现身钦命字符的个数,重临三个大背头

    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

   
count(self,sub,start=None,end=None卡塔尔(قطر‎是用来总括字符串中冒出一定字符的个数,重返八个整数,实比如下:

    >>> name = “Alexssbbafadgcxlsdgpssl”
    >>> name.count(“a”)
  2
    >>> name.count(“D”)
  0
    总结字符串中现身内定字符的个数,当荒诞不经的时候再次回到0。

    12.encode(self,encoding=’utf-8′,errors=’strict’)

    def encode(self, encoding=’utf-8′, errors=’strict’): # real
signature unknown; restored from __doc__
    ”””
    S.encode(encoding=’utf-8′, errors=’strict’) -> bytes
        编码
    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””

    实举个例子下:

    >>> name = “李杰”
  >>> name.encode(“gbk”)
  b’\xc0\xee\xbd\xdc’
    将字符串转变为”gbk”格式,机器度和胆识其余格式。

    13.endswith(self,suffix,start=None,end=None)

    def endswith(self, suffix, start=None, end=None): # real signature
unknown; restored from __doc__
    ”””
    S.endswith(suffix[, start[, end]]) -> bool
       
字符串是不是以钦点的字符结束,endswith(self,suffix,start=None,end=None卡塔尔(قطر‎
    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

   
endswith(self,suffix,start=None,end=None卡塔尔(英语:State of Qatar)判别字符串以某个钦点的字符截止,假使是,则赶回布尔值True;否则重返False。

    >>> name = “Alexsssbdfgedlmnopqqsstabsc”
  >>> name.endswith(“c”)
  True
  >>> name.endswith(“s”,0,5)
  True
    14.expandtabs(self,tabsize=8)

    def expandtabs(self, tabsize=8): # real signature unknown; restored
from __doc__
    ”””
    S.expandtabs(tabsize=8) -> str
       
将字符串中的tab键转变为空格,默许时8个职位的空格,能够和煦安装参数
    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 “”

   
expandtabs(self,tabsize=8卡塔尔国将字符串中的tab(\t卡塔尔将转速为空格,暗中同意是转账为8个空格,能够和煦安装转化为多少个空格。示举个例子下:

    >>> user = ”    Alex”
  >>> user.expandtabs()
  ’        Alex’
  >>> user.expandtabs(2)
  ’  Alex’
  >>> user.expandtabs(0)
  ’Alex’
  >>> user.expandtabs(tabsize=3)
  ’   Alex’
    15.find(self,sub,start=None,end=None)

    def find(self, sub, start=None, end=None): # real signature
unknown; restored from __doc__
    ”””
    S.find(sub[, start[, end]]) -> int
       
查找钦点字符在字符串中的地点,重回地点索引,假设搜索不到,则赶回-1(return
-1 on failure卡塔尔(قطر‎
    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
   
find(self,sub,start=None,end=None卡塔尔国查找钦命字符在字符串中的地点,假诺搜索不到,则赶回-1(即查找字符一纸空文钦赐字符串中卡塔尔(英语:State of Qatar),示比方下:

    >>> name
  ’Alexsssbdfgedlmnopqqsstabsc’
  >>> name.find(“s”)
  4
  >>> name.find(“s”,8,len(name)-1)
  20
  >>> name.find(“S”)
  -1
   
find(self,sub,start=None,end=None卡塔尔国查找那个字符第2回面世的地点索引。只查找第二个岗位索引,查找未果再次来到-1.
    16.index(self,sub,start=None,end=None)

    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

     
index(self,sub,start=None,end=None卡塔尔(英语:State of Qatar)跟find(卡塔尔(قطر‎相疑似寻觅钦赐字符在字符串中之处索引,区别的是,假设index(卡塔尔查找未果,则报错。搜索不到报错。 
示举例下:

     >>> name
  ’Alexsssbdfgedlmnopqqsstabsc’
  >>> name.index(“s”)
  4
  >>> name.index(“s”,8,len(name)-1)
  20
  >>> name.index(“S”)
  Traceback (most recent call last):
     File “<stdin>”, line 1, in <module>
  ValueError: substring not found    
上边能够观看,index(卡塔尔和find(卡塔尔(英语:State of Qatar)是千篇黄金年代律的,都以回来寻觅字符之处索引,可是当index(卡塔尔(قطر‎查找不到的时候会报错。

    17.format_map(self,mapping)

    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 “”

    18.isalnum(self)

    def isalnum(self): # real signature unknown; restored from
__doc__
    ”””
    S.isalnum() -> bool
       判别字符串中具有的字符是还是不是都是字符数字组成
    Return True if all characters in S are alphanumeric
    and there is at least one character in S, False otherwise.
    ”””
    return False
   
示比方下:决断字符串中是还是不是富有因素独有数字和字母组成,alnum是单词阿尔法numeric的缩写,字母数字
    >>> name.isalnum()
  True
  >>> nums = “2233”
  >>> nums.isalnum()
  True

    19.isalpha()

    def isalpha(self): # real signature unknown; restored from
__doc__
    ”””
    S.isalpha() -> bool
        决断字符串中全数的因素是不是都以字母组成
    Return True if all characters in S are alphabetic
    and there is at least one character in S, False otherwise.
    ”””
    return False

   
推断字符串全数字符是还是不是都以字母alpha是单词alphabetic(字母)的缩写:  

>>> nums = “2233”
  >>> name.isalpha()
  True
  >>> nums.isalpha()
  False
    20.isdecimal(self)

    def isdecimal(self): # real signature unknown; restored from
__doc__
    ”””
    S.isdecimal() -> bool
       
倘诺字符串中值富含十进制的数字,则赶回True;不然再次来到布尔值False.
    Return True if there are only decimal characters in S,
    False otherwise.
    ”””
    return False

   
isdecimal(self卡塔尔(قطر‎判定字符串中是还是不是只含有十进制的数字,假设是,则赶回True;不然再次回到False。示举个例子下:

    >>> s1 = “a122”
  >>> s2 = “222”
  >>> s3 = “&b#s”
  >>> s1.isdecimal()
  False
  >>> s2.isdecimal()
  True
  >>> s3.isdecimal()
  False
    21.isdigit(self)
    def isdigit(self): # real signature unknown; restored from
__doc__
    ”””
    S.isdigit() -> bool
        推断字符串是否唯有由数字构成
    Return True if all characters in S are digits
    and there is at least one character in S, False otherwise.
    ”””
    return False

   
isdigit(self卡塔尔国剖断字符串中是还是不是唯有包罗数字,即由数字组成的字符串。实举例下:

    >>> s1 = “a122”
  >>> s2 = “222”
  >>> s3 = “&b#s”

    >>> s1.isdigit()
  False
  >>> s2.isdigit()
  True
  >>> s3.isdigit()
  False
    22.isidentifier(self)

    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

    isidentifier(self卡塔尔国,实举个例子下:

    >>> s2 = “Alex”
  >>> s3 = “list”
  >>> s2.isidentifier()
  True
  >>> s3.isidentifier()
  True
  >>> s4 = “55”
  >>> s4.isidentifier()
  False
  >>> s5 = “gengcx”
  >>> s5.isidentifier()
  True

    23.islower(self)

    def islower(self): # real signature unknown; restored from
__doc__
    ”””
    S.islower() -> bool
        决断是不是皆以小写
    Return True if all cased characters in S are lowercase and
there is
    at least one cased character in S, False otherwise.
    ”””
    return False

    islower(self卡塔尔(قطر‎剖断字符串是还是不是都以小写,

    >>> s1 = “Alex”
  >>> s2 = “23abc”
  >>> s3 = “alex”
  >>> s4 = “AlexSb&&”
  >>> s5 = “a%@”
  >>> s1.islower()
  False
  >>> s2.islower()
  True
  >>> s3.islower()
  True
  >>> s4.islower()
  False
  >>> s5.islower()
  True
    24.isnumeric(self)

    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

   
isnumeric(self卡塔尔国判定字符串S中是不是值包罗数字在内部,借使是,再次来到True;不然重回False.

    >>> name = “Alex222”
  >>> nums = “234239”
  >>> num = “23se”
  >>> l1 = “2.35”
  >>> name.isnumeric()
  False
  >>> nums.isnumeric()
  True
  >>> num.isnumeric()
  False
  >>> l1.isnumeric()
  False
    25.isprintable(self)

    def isprintable(self): # real signature unknown; restored from
__doc__
    ”””
    S.isprintable() -> bool
      
判定三个字符串是还是不是里面包车型地铁字符都以足以打字与印刷出来的照旧字符串是空的,假设是回去True;不然再次回到False
    Return True if all characters in S are considered
    printable in repr() or S is empty, False otherwise.
    ”””
    return False

    isprintable(self) 

    >>> name = ”    Alex”
  >>> name.isprintable()
  False
  >>> user = “Alex”
  >>> user.isprintable()
  True

    >>> s1 = “”
    >>> s1.isprintable()
  True
    isprintable(s1卡塔尔国中s1是空的字符串,不过也回到True.
    26.isspace(self)

    def isspace(self): # real signature unknown; restored from
__doc__
    ”””
    S.isspace() -> bool
        推断字符串中是还是不是都以一无所有
    Return True if all characters in S are whitespace
    and there is at least one character in S, False otherwise.
    ”””
    return False

   
isspace(self卡塔尔国判定字符串中是还是不是都以空荡荡,如若是回来True;不然重临False。示举个例子下:

    >>> s1 = ”    “
  >>> s2 = ”       “
  >>> s3 = “cs   “
  >>> s1.isspace()
  True
  >>> s2.isspace()
  True
  >>> s3.isspace()
  False
    27.istitle(self)

    def istitle(self): # real signature unknown; restored from
__doc__
    ”””
    S.istitle() -> bool
        推断字符串中兼有字符是或不是是首字母大写方式,假若是回去True
    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

   
istitle(self)推断是还是不是首字母大写,如若是回来True;不然重返False。实比方下:

    >>> s1 = “Alex is sb”
  >>> s2 = “Alex Is Sb”
  >>> s3 = “alex is sb”
  >>> s1.istitle()
  False
  >>> s2.istitle()
  True
  >>> s3.istitle()
  False
    28.isupper(self)

    def isupper(self): # real signature unknown; restored from
__doc__
    ”””
    S.isupper() -> bool
        判别全部字母是不是都以大写
    Return True if all cased characters in S are uppercase and
there is
    at least one cased character in S, False otherwise.
    ”””
    return False
      isupper(self卡塔尔判别字符串中装有字符是或不是都是大写情势:实比如下:

    >>> s1 = “Alex is sb”
  >>> s2 = “Alex Is Sb”
    >>> s3 = “alex is sb”

    >>> s4 = “ALEX IS SB”
    >>> s1.isupper()
  False
  >>> s2.isupper()
  False
  >>> s3.isupper()
  False

    >>> s4.isupper()
  True

    29.join(self,iterable)

    def join(self, iterable): # real signature unknown; restored from
__doc__
    ”””
    S.join(iterable) -> str
        字符串的拼凑,把字符串拼接到一起
    Return a string which is the concatenation of the strings in
the
    iterable. The separator between elements is S.
    ”””
    return “”
   
join(self,iterable卡塔尔国拼接,字符串和列表直接的拼凑,有两样措施的拼接,上边来商量一下:

    >>> sign = “-“
  >>> name = “alex”
  >>> li = [“a”,”l”,”e”,”x”,”s”,”b”]
  >>> l1 = “”
   
1.字符串和字符串进行拼接,将拼接中的字符串的每叁个因素与字符串中的成分进行拼接,即iterable+self+iterable+self… 

  >>sign.join(name)
  ’a-l-e-x’
  >>> name.join(“sb”)
  ’salexb’
  >>> name.join(“issb”)
  ’ialexsalexsalexb’
  2.字符串和列表进行拼接,列表中的每三个成分都与字符串的成分实行拼接:

  >>> sign.join(li)
  ’a-l-e-x-s-b’
  >>> l1.join(li)
  ’alexsb’

   
其实在Python中,字符串存款和储蓄的格式就是列表存款和储蓄的,比如”alexsb”存款和储蓄便是[“a”,”l”,”e”,”x”,”s”,”b”],由此字符串与列表拼接与字符串与字符串拼接是平等的。

    30.ljust(self,width,fillchar=None)

    def ljust(self, width, fillchar=None): # real signature unknown;
restored from __doc__
    ”””
    S.ljust(width[, fillchar]) -> str
       固定长度,字符串侧面拼接内定的字符
    Return S left-justified in a Unicode string of length width.
Padding is
    done using the specified fill character (default is a space).
    ”””
    return “”
    ljust(self,width,fillchar=None卡塔尔(قطر‎,固定长度,self+fillchar,实比如下:

    >>> name = “alexsb”
    >>> name.ljust(12,”-“)
  ’alexsb——‘

    31.rjust(self,width,fillchar=None)

    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 “”
    固定字符串长度,在字符串左边链接钦赐字符,实比如下:

    >>> name = “alexsb”   

  >>> name.rjust(12,”-“)
  ’——alexsb’

    32.lower(self)

    def lower(self): # real signature unknown; restored from
__doc__
    ”””
    S.lower() -> str
        将字符串全体倒车为小写情势
    Return a copy of the string S converted to lowercase.
    ”””
    return “”
    33.lstrip(self,chars=None)

    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 “”
   
lstrip(self,chars=None卡塔尔(قطر‎是删除字符串左边的空格,暗许是剔除空格,其实能够钦命删除任何字符,实譬如下:

    >>> name = ”   AlexAesbb   “
  >>> name.lstrip()
  ’AlexAesbb   ‘

    34.rstrip(self,chars=None)

    def rstrip(self, chars=None): # real signature unknown; restored
from __doc__
    ”””
    S.rstrip([chars]) -> str
        删除字符串左边的空格
    Return a copy of the string S with trailing whitespace
removed.
    If chars is given and not None, remove characters in chars
instead.
    ”””
    return “”
    rstrip(self,chars=None卡塔尔国删除字符串侧边的空格,实比方下:

    >>> name = ”   AlexAesbb   ”   

    >>> name.rstrip()
‘   AlexAesbb’

    35.strip(self,chars=None)

    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 “”
     strip(self,chars=None卡塔尔删除字符串两边的空格,示举例下:

    >>> name = ”   AlexAesbb   ”   

    >>> name.strip()
  ’AlexAesbb’

    36.maketrans(self,*args,**kwargs)

    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
    37.translate(self,table)

    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 “”
    示举例下:

    >>> intab = “aeiou”
  >>> outtab = “12345”

    >>> trantab = intab.maketrans(intab,outtab)
  >>> trantab
  {97: 49, 111: 52, 117: 53, 101: 50, 105: 51}

    >>> str = “This is string example …. wow!!!”
    >>> str.translate(trantab)
  ’Th3s 3s str3ng 2x1mpl2 …. w4w!!!’

   
上边代码含义是,把intab中各种成分与outtab中每一个成分大器晚成黄金年代对应,然后translate(卡塔尔国替换个中对应的因素。

    38.partition(self,sep)

    def partition(self, sep): # real signature unknown; restored from
__doc__
    ”””
    S.partition(sep) -> (head, sep, tail)
        字符串分隔,以sep分隔为前中后三部分
    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
   
partition(self,sep卡塔尔国字符串分隔,以字符串sep分隔为前中后三部分,况兼以找到的首先个字符为分隔:

    >>> name = ‘   AlexAesbb   ‘
  >>> name.partition(“x”)
  (‘   Ale’, ‘x’, ‘Aesbb   ‘)
  >>> name.partition(“A”)
  (‘   ‘, ‘A’, ‘lexAesbb   ‘)

    39.replace(self,old,new,count=None)

    def replace(self, old, new, count=None): # real signature unknown;
restored from __doc__
    ”””
    S.replace(old, new[, count]) -> str
        字符串的查找替换
    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 “”
   
字符串的替换,old哪个字符要替换,new替换来什么,count替换多少个,实举个例子下:

    >>> name = ‘   AlexAesbb   ‘
  >>> name.replace(“A”,”M”)
  ’   MlexMesbb   ‘
  >>> name.replace(“A”,”M”,1)
  ’   MlexAesbb   ‘

    字符串的追寻替换,暗许替换全体,能够钦点替换的个数。

    39.rfind(self,sub,start=None,end=None)

    def rfind(self, sub, start=None, end=None): # real signature
unknown; restored from __doc__
    ”””
    S.rfind(sub[, start[, end]]) -> int
        从左边伊始查找
    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
    从字符串右边领头查找,查找钦命字符在字符串中的地点索引:实比如下:

    >>> name = ‘   AlexAesbb   ‘
  >>> name.rfind(“A”)
  7
  >>> name.find(“A”)
  3
  >>> name.rfind(” “)
  14

    从左侧查找内定字符在字符串中之处索引,固然找出不到再次来到-1.

    40.rindex(self,sub,start=None,end=None)

    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
   
rindex(self,sub,start=None,end=None卡塔尔(قطر‎从字符串右边查找钦命字符的地点索引,假如寻找不到就能报错。

    41.rpartition(self,sep)

    def rpartition(self, sep): # real signature unknown; restored from
__doc__
    ”””
    S.rpartition(sep) -> (head, sep, tail)
        从字符串右边最早查找分隔
    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
   
rpartition(self,sep卡塔尔国从字符串左边最早查找分隔,与partition(self,sep卡塔尔适逢其时相反,示譬喻下,分隔字符串获得多个元组:

    >>> name = ‘   AlexAesbb   ‘
  >>> name.partition(“A”)
  (‘   ‘, ‘A’, ‘lexAesbb   ‘)
  >>> name.rpartition(“A”)
  (‘   Alex’, ‘A’, ‘esbb   ‘)

    42.rsplit(self,sep=None,maxsplit=-1)

    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 []
   
rsplit(self,sep=None,maxsplit=-1卡塔尔分隔字符串,并扭转叁个存放的列表,实举个例子下:

    >>> name = “Alexsbegcex”
  >>> name.split(“e”)
  [‘Al’, ‘xsb’, ‘gc’, ‘x’]
  >>> name.rsplit(“e”)
  [‘Al’, ‘xsb’, ‘gc’, ‘x’]

    >>> name.split(“e”,0)
  [‘Alexsbegcex’]
  >>> name.split(“e”,1)
  [‘Al’, ‘xsbegcex’]
  >>> name.split(“e”,2)
  [‘Al’, ‘xsb’, ‘gcex’]
  >>> name.split(“e”,3)
  [‘Al’, ‘xsb’, ‘gc’, ‘x’]
  >>> name.split(“e”,4)
  [‘Al’, ‘xsb’, ‘gc’, ‘x’]
  >>> name.split(“e”,-1)
  [‘Al’, ‘xsb’, ‘gc’, ‘x’]

   
以钦赐字符串分隔,而且替换钦赐字符,分隔变成一个列表,能够钦赐分隔字符的个数。

    43.split(self,sep=None,maxsplit=-1)

    def split(self, sep=None, maxsplit=-1): # real signature unknown;
restored from __doc__
    ”””
    S.split(sep=None, maxsplit=-1) -> list of strings
        分隔字符串,生成多少个列表,可以钦命分隔的次数,暗中认可是全体相间
    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 []
    44.splitlines(self,keepends=None)

    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 []
   
splitlines(self,keepends=None)以”\n”换行符的情势分隔字符串,实举个例子下:

    >>> user = “””
  … alex
  … aoi
  … marry”””

    >>> user.splitlines()
  [”, ‘alex’, ‘aoi’, ‘marry’]

    45.startswith(self,prefix,start=None,end=None)

    def startswith(self, prefix, start=None, end=None): # real
signature unknown; restored from __doc__
    ”””
    S.startswith(prefix[, start[, end]]) -> bool
        字符串是或不是以钦定字符开首,能够钦命起始地点
    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
   
startswith(self,prefix,start=None,end=None卡塔尔(英语:State of Qatar)判定字符串是不是以内定字符最初,能够钦定开头地点,与endswith(self,prefix,start=None,end卡塔尔(英语:State of Qatar)

正巧相反,示比如下:

    >>> name = ‘Alexsbegcex’
    >>> name.startswith(“A”)
  True
    >>> name.startswith(“w”)
  False

    >>> name.startswith(“e”,2,5)
  True

    46.swapcase(self)

    def swapcase(self): # real signature unknown; restored from
__doc__
    ”””
    S.swapcase() -> str
        将一个字符串中持有大写字符调换为小写,小写调换为题写
    Return a copy of S with uppercase characters converted to
lowercase
    and vice versa.
    ”””
    return “”
   
swapcase(self卡塔尔国将一个字符串中存有字符小写转变为大写,大写转化为小写,好贱呀那个方法,实举例下:

    >>> name = ‘Alexsbegcex’
  >>> name.swapcase()
  ’aLEXSBEGCEX’

    47.title(self)

    def title(self): # real signature unknown; restored from
__doc__
    ”””
    S.title() -> str
        将字符串首字母调换为题写
    Return a titlecased version of S, i.e. words start with title
case
    characters, all remaining cased characters have lower case.
    ”””
    return “”
    48.upper(self)

    def upper(self): # real signature unknown; restored from
__doc__
    ”””
    S.upper() -> str
        将字符串全体字母都退换为题写
    Return a copy of S converted to uppercase.
    ”””
    return “”
    49.zfill(self,width)

    def zfill(self, width): # real signature unknown; restored from
__doc__
    ”””
    S.zfill(width) -> str
        钦命宽度,不足左边补零
    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 “”
    zfill(self,width卡塔尔(قطر‎钦点宽度,不足左边补0,否则不改变。实举个例子下:

    >>> name = ‘Alexsbegcex’
  >>> name.zfill(20)
  ’000000000Alexsbegcex’
  >>> name.zfill(5)
  ’Alexsbegcex’
    50.__contains__(self,*args,**kwargs)

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

        判别字符串中是还是不是含有钦命字符
    pass
   
__contains__(self,*args,**kwargs卡塔尔(قطر‎决断字符串中是不是含有钦赐字符,实举例下:

    >>> name = ‘Alexsbegcex’
  >>> name.__contains__(“e”)
  True
  >>> name.__contains__(“E”)
  False

   
 

 

字符串是编制程序中常用的类别,字符型在内部存款和储蓄器中是以单个情势储存的,比方name =
“alex”,在内部存款和储蓄器中存放的款式为…

语法

casefold(卡塔尔(英语:State of Qatar)方意大利语法:

S.casefold()

 

2. 格式调整音讯

   format(卡塔尔(英语:State of Qatar)方法中<模板字符串>的槽除了席卷参数序号,还可以富含格式调节新闻。此时,槽的内部样式如下:

     {<参数序号>: <格式调节标志>}

     其中,<格式调控标志>用来调整参数字展现示时的格式,满含:<填充><对齐><宽度>,<.精度><类型>6
个字段,那个字段都是可选的,能够结合使用,逐条介绍如下。

 

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<宽度>

指当前槽的设定输出字符宽度,如若该槽对应的format(卡塔尔(قطر‎参数长度比<宽度>设定值大,则选拔参数实际尺寸。假设该值的其实位数小于钦命宽度,则位数将被暗中同意以空格字符补充。

<对齐>

指参数在<宽度>内输出时的对齐方式,分别使用<、>和^五个标记表示左对齐、右对齐和居中对齐。

<填充>

指<宽度>内除了参数外的字符接Nash么方法意味着,私下认可使用空格,能够经过<填充>改换。

s = "PYTHON"

"{0:30}".format(s)
Out[17]: 'PYTHON                        '

"{0:>30}".format(s)
Out[18]: '                        PYTHON'

"{0:*^30}".format(s)
Out[19]: '************PYTHON************'

"{0:-^30}".format(s)
Out[20]: '------------PYTHON------------'

"{0:3}".format(s)
Out[21]: 'PYTHON'

参数

  • str — 钦点检索的字符串
  • beg — 开端索引,默以为0。
  • end — 截止索引,暗许为字符串的长度。

返回值

回去将字符串中装有大写字符转换为小写后转移的字符串。

逗号(,)

<格式调控标识>中逗号(,)用于体现数字的千位分隔符,举个例子:

"{0:-^20,}".format(1234567890)
Out[24]: '---1,234,567,890----'

"{0:-^20}".format(1234567890) #对比输出
Out[25]: '-----1234567890-----'

"{0:-^20,}".format(12345.67890)
Out[26]: '----12,345.6789-----'

返回值

如果带有子字符串重回开头的索引值,不然重临-1。

实例

以下实例显示了casefold(卡塔尔方法的实例:

#!/usr/bin/python3

S1 = "Runoob EXAMPLE....WOW!!!" #英文
S2 = "ß"  #德语

print( S1.lower() )
print( S1.casefold() )
print( S2.lower() )
print( S2.casefold() ) #德语的"ß"正确的小写是"ss"

  

上述实例输出结果如下:

runoob example....wow!!!
runoob example....wow!!!
ß
ss

 

 <.精度>

表示五个意思,由小数点(.)开端。对于浮点数,精度表示小数部分输出的有效位数。对于字符串,精度表示输出的最大尺寸。

"{0:.2f}".format(12345.67890)
Out[29]: '12345.68'

"{0:H^20.3f}".format(12345.67890)
Out[30]: 'HHHHH12345.679HHHHHH'

"{0:.4}".format("PYTHON")
Out[31]: 'PYTH'

实例

以下实例呈现了find(卡塔尔(英语:State of Qatar)方法的实例:

#!/usr/bin/python3

str1 = "Runoob example....wow!!!"
str2 = "exam";

print (str1.find(str2))
print (str1.find(str2, 5))
print (str1.find(str2, 10))

 

上述实例输出结果如下:

7
7
-1

实例

>>>info = 'abca'
>>> print(info.find('a'))      # 从下标0开始,查找在字符串里第一个出现的子串,返回结果:0
0
>>> print(info.find('a', 1))   # 从下标1开始,查找在字符串里第一个出现的子串:返回结果3
3
>>> print(info.find('3'))      # 查找不到返回-1
-1
>>>

 

<类型>

意味着输出整数和浮点数类型的格式准则。对于整数类型,输出格式包罗6 种:

  • b: 输出整数的二进制格局;
  • c: 输出整数对应的 Unicode 字符;
  • d: 输出整数的十进制形式;
  • o: 输出整数的八进制情势;
  • x: 输出整数的小写十二进制方式;
  • X: 输出整数的大写十七进制情势;

    “{0:b},{0:c},{0:d},{0:o},{0:x},{0:X}”.format(425)
    Out[32]: ‘110101001,Ʃ,425,651,1a9,1A9’

对此浮点数类型,输出格式包蕴4 种:

  • e: 输出浮点数对应的小写字母 e 的指数格局;
  • E: 输出浮点数对应的大写字母 E 的指数格局;
  • f: 输出浮点数的正规浮点情势;
  • %: 输出浮点数的百分款式。

     浮点数输出时尽恐怕采用<.精度>表示小数部分的幅度,有帮忙越来越好调整输出格式。

"{0:e},{0:E},{0:f},{0:%}".format(3.14)
Out[33]: '3.140000e+00,3.140000E+00,3.140000,314.000000%'

"{0:.2e},{0:.2E},{0:.2f},{0:.2%}".format(3.14)
Out[34]: '3.14e+00,3.14E+00,3.14,314.00%'

 

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