这是本人在学习python过程中总结的一些关于字符串的常用的方法.

文中引用了python3.5版本内置的帮助文档,大致进行翻译,并添加了几个小实验.

isalnum

S.isalnum() -> bool #字符串里所有的字符都是字母或者数字时返回True,否则返回False

Return True if all characters in S are alphanumeric and there is

at least one character in S, False otherwise.

>>> str1="hello world"

>>> str2="hello555 world"

>>> str3="66666"

>>> str4="hello"

>>> str1.isalnum()

False

>>> str2.isalnum()

False

>>> str3.isalnum()

True

>>> str4.isalnum()

True

isalpha

S.isalpha() -> bool #字符串里所有的字符都是字母时返回True,否则返回False

Return True if all characters in S are alphabetic and there is

at least one character in S, False otherwise.

>>> str1="hello world"

>>> str2="hello555 world"

>>> str3="66666"

>>> str4="hello"

>>> str1.isalpha()

False

>>> str2.isalpha()

False

>>> str3.isalpha()

False

>>> str4.isalpha()

True

isdigit#####

S.isdigit() -> bool #字符串里所有字符都是数字则返回True,否则返回False

Return True if all characters in S are digits and there is at

least one character in S, False otherwise.

>>> str1="hello world"

>>> str2="hello555 world"

>>> str3="66666"

>>> str1.isdigit()

False

>>> str2.isdigit()

False

>>> str3.isdigit()

True

islower

S.islower() -> bool #字符串所有的字符都是小写字母时返回True,否则返回False

Return True if all cased characters in S are lowercase and there is

at least one cased character in S, False otherwise.

>>> str1="hello world"

>>> str2="66666"

>>> str3="HELLO WORLD"

>>> str1.islower()

True

>>> str2.islower()

False

>>> str3.islower()

False

istitle

S.istitle() -> bool #每个单词的首字母大写时返回True,否则返回False

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.

>>> str1="hello world"

>>> str2="Hello World"

>>> str3="HELLO WORLD"

>>> str1.istitle()

False

>>> str2.istitle()

True

>>> str3.istitle()

False

isupper

S.isupper() -> bool #字符串里所有的字符都是大写字母时返回True,否则返回False

Return True if all cased characters in S are uppercase and there is

at least one cased character in S, False otherwise.

>>> str1="hello world"

>>> str2="66666"

>>> str3="HELLO WORLD"

>>> str1.isupper()

False

>>> str2.isupper()

False

>>> str3.isupper()

True

lower

S.lower() -> str #把字符串里所有的字符都转换为小写字母

Return a copy of the string S converted to lowercase.

>>> str3="HELLO WORLD"

>>> str3.lower()

'hello world'

upper

S.upper() -> str #把字符串里所有的字符都转换为大写字母

Return a copy of S converted to uppercase.

>>> str1="hello world"

>>> str1.upper()

'HELLO WORLD'

strip

S.strip([chars]) -> str #去除字符串里的空格

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.

>>> str1="     hello world      "

>>> str2="hello world       "

>>> str1.strip()

'hello world'

>>> str2.strip()

'hello world'

isspace

S.isspace() -> bool #字符串里所有的字符都为空格时返回True,否则返回False

Return True if all characters in S are whitespace

and there is at least one character in S, False otherwise.

>>> str1="             "

>>> str2="hello world"

>>> str1.isspace()

True

>>> str2.isspace()

False

replace

S.replace(old, new[, count]) -> str #把字符串里指定的字符替换成新的字符

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.

>>> str1="hello world"

>>> str1.replace("l","L")

'heLLo worLd'

>>> str2="abababababababab"

>>> str2.replace("a","c")

'cbcbcbcbcbcbcbcb'

index

S.index(sub[, start[, end]]) -> int #返回字符串里的子字符串的索引

Like S.find() but raise ValueError when the substring is not found.

>>> str1="abcdefg"

>>> str1.index("a")

0

>>> str1.index("f")

5

find

S.find(sub[, start[, end]]) -> int #在字符串里查找指定的子串,未找到时返回-1,找到则返回子串在字符串中的索引值

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.

>>> str1="abcdefg"

>>> str2="ababab"

>>> str1.find("bc")

1

>>> str2.find("b")

1

>>> str1.find("f")

5

split

S.split(sep=None, maxsplit=-1) -> list of strings #根据指定的符号分隔字符串

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.

>>> str1="/etc/sysconfig/selinux"

>>> str1.split("/")

['', 'etc', 'sysconfig', 'selinux']

>>> str2="abc|mnt|xyz"

>>> str2.split("|")

['abc', 'mnt', 'xyz']

startswith

S.startswith(prefix[, start[, end]]) -> bool #字符串以指定的字符开头时返回True,否则返回False

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.

>>> str1="hello world"

>>> str2="abcdefg"

>>> str1.startswith("hello")

True

>>> str2.startswith("abc")

True

endswith

S.endswith(suffix[, start[, end]]) -> bool #字符串以指定的字符结尾时返回True,否则返回False

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.

>>> str1="hello world"

>>> str2="abcdefg"

>>> str1.startswith("hello")

True

>>> str2.startswith("abc")

True

>>> str1.endswith("ld")

True

>>> str2.endswith("fg")

True

lstrip

S.lstrip([chars]) -> str #仅去除字符串左边的空格

Return a copy of the string S with leading whitespace removed.

If chars is given and not None, remove characters in chars instead.

>>> str1="           hello world         "

>>> str2="            hello world"

>>> str3="hello world            "

>>> str1.lstrip()

'hello world         '

>>> str2.lstrip()

'hello world'

>>> str3.lstrip()

'hello world            '

rstrip

S.rstrip([chars]) -> str #仅去除字符串右边的空格

Return a copy of the string S with trailing whitespace removed.

If chars is given and not None, remove characters in chars instead.

>>> str1="           hello world         "

>>> str2="            hello world"

>>> str3="hello world            "

>>> str1.rstrip()

'           hello world'

>>> str2.rstrip()

'            hello world'

>>> str3.rstrip()

'hello world'

rfind

S.rfind(sub[, start[, end]]) -> int #返回子串在字符串中的索引值

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.

>>> str1="hello world"

>>> str2="abcdefg"

>>> str1.rfind("world")

6

>>> str1.rfind("r")

8

>>> str2.rfind("e")

4

>>> str2.rfind("g")

6

format

S.format(*args, **kwargs) -> str #格式化输出指定的字符串

Return a formatted version of S, using substitutions from args and kwargs.

The substitutions are identified by braces ('{' and '}').

>>> print("{name}======>{age}".format(name="tom",age=22))

tom=========>22

>>> print("{name}======>{age}".format(age=22,name="tom"))

tom=========>22

swapcase

S.swapcase() -> str #把字符串中的小写字母变成大写,大写字母变成小写

Return a copy of S with uppercase characters converted to lowercase

and vice versa.

>>> str1="HELLO world"

>>> str1.swapcase()

'hello WORLD'

>>> str2="hello WORLD"

>>> str2.swapcase()

'HELLO world'

title

S.title() -> str #把字符串中的每个单词变成大写字母开头

Return a titlecased version of S, i.e. words start with title case

characters, all remaining cased characters have lower case.

>>> str1="hello world"

>>> str1.title()

'Hello World'

>>> str2="this is a test string"

>>> str2.title()

'This Is A Test String'

join

S.join(iterable) -> str #把字符串混合插入到一个迭代器中

Return a string which is the concatenation of the strings in the

iterable. The separator between elements is S.

>>> str1="abcd"

>>> str2="xyz"

>>> str1.join(str2)

'xabcdyabcdz'

capitalize

S.capitalize() -> str #把字符串中的首字母变成大写

Return a capitalized version of S, i.e. make the first character

have upper case and the rest lower case.

>>> str1="hello world"

>>> str1.capitalize()

'Hello world'

>>> str1="linux"

>>> str1.capitalize()

'Linux'

center

S.center(width[, fillchar]) -> str #扩充字符串到指定长度,不够则用第二个参数的字符填充,默认为空格

Return S centered in a string of length width. Padding is

done using the specified fill character (default is a space)

>>> str1="hello world"

>>> str1.center(30,"#")

'############linux#############'

>>> str2="linux"

>>> str2.center(16,"*")

'*****linux******'

count

S.count(sub[, start[, end]]) -> int #判断子串在字符串中出现的次数

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.

>>> str1="hello world"

>>> str1.count("l")

3

>>> str2="aaaaaaaaaaaa"

>>> str2.count("a")

12

ljust

S.ljust(width[, fillchar]) -> str #扩充字符串到指定长度,不足则由第二个参数从右边填充,默认为空格

Return S left-justified in a Unicode string of length width. Padding is

done using the specified fill character (default is a space).

>>> str1="hello world"

>>> str1.ljust(20,"@")

'hello world@@@@@@@@@'

>>> str2="linux"

>>> str2.ljust(18,"&")

'linux&&&&&&&&&&&&&'

rjust

S.rjust(width[, fillchar]) -> str #扩充字符串到指定长度,不足由第二个参数从左边填充,默认为空格

Return S right-justified in a string of length width. Padding is

done using the specified fill character (default is a space).

>>> str1="hello world"

>>> str2="linux"

>>> str1.rjust(30,"#")

'###################hello world'

>>> str2.rjust(14,"$")

'$$$$$$$$$linux'

rsplit

S.rsplit(sep=None, maxsplit=-1) -> list of strings #从文件尾部开始按指定的分隔符切分字符串

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.

>>> str1="hello/world/people"

>>> str1.rsplit("/")

['hello', 'world', 'people']

>>> str2="/etc/sysconfig/selinux"

>>> str2.rsplit("/")

['', 'etc', 'sysconfig', 'selinux']

expandtabs

S.expandtabs(tabsize=8) -> str #按照所给的参数把一个制表符转换成指定的空格,默认为转换为8个空格

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.

>>> str1="hello\tworld"

>>> print(str1)

hello	world

>>> str1.expandtabs()

'hello   world'

>>> str1.expandtabs(8)

'hello   world'

>>> str1.expandtabs(2)

'hello world'

>>> str1.expandtabs(12)

'hello       world'

rindex

S.rindex(sub[, start[, end]]) -> int #返回子串在字符串中的索引值,未找到则抛出异常

Like S.rfind() but raise ValueError when the substring is not found.

>>> str1="abcdefghijklmn"

>>> str1.rindex("abc")

0

>>> str1.rindex("efg")

4

>>> str1.rindex("g")

6

>>> str1.rindex("m")

12

isprintable

S.isprintable() -> bool #字符里所有的字符都为可打印字符时返回True,否则返回False

Return True if all characters in S are considered

printable in repr() or S is empty, False otherwise.

>>> str1="              "

>>> str2="hello world"

>>> str1.isprintable()

True

>>> str2.isprintable()

True

>>> str3="\t"

>>> print(str3)

>>> str3.isprintable()

False

splitlines

S.splitlines([keepends]) -> list of strings #按照换行符分隔字符串,返回分隔后的列表

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.

>>> str1="hello \e world"

>>> print(str1)

hello \e world

>>> str1.splitlines()

['hello \\e world']

>>> type(str1.splitlines())

<class 'list'>

>>> str2="hello world"

>>> str2.splitlines()

['hello world']

format_map

S.format_map(mapping) -> str #格式化输出字符串

Return a formatted version of S, using substitutions from mapping.

The substitutions are identified by braces ('{' and '}').

>>> str1="hello world {lang}"

>>> lang="python"

>>> print(str1.format_map(vars()))

hello world python

>>> str2="{os} {database} {webserver} python"

>>> os="linux"

>>> database="mysql"

>>> webserver="apache"

>>> print(str2.format_map(vars()))

linux mysql apache python

isnumeric

S.isnumeric() -> bool #字符串里所有的字符都是数字时返回True,否则返回False

Return True if there are only numeric characters in S,

False otherwise.

>>> str1="123456"

>>> str2="123.456"

>>> str3="hello world"

>>> str1.isnumeric()

True

>>> str2.isnumeric()

False

>>> str3.isnumeric()

False

partition

S.partition(sep) -> (head, sep, tail) #按照给定的字符分隔字符串,返回一个元组,如果给定的字符串有多个,则以第一个索引为准

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.

>>> str1="hello world"

>>> str1.partition(" ")

('hello', ' ', 'world')

>>> str1.partition("l")

('he', 'l', 'lo world')

>>> str1.partition("w")

('hello ', 'w', 'orld')

rpartition

S.rpartition(sep) -> (head, sep, tail) #按照给定的字符分隔字符串,返回一个元组

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.

>>> str1="abcdefg"

>>> str1.rpartition("b")

('a', 'b', 'cdefg')

>>> str1.rpartition("d")

('abc', 'd', 'efg')

>>> str1.rpartition("g")

('abcdef', 'g', '')

python字符串常用的方法解析的更多相关文章

  1. Python字符串常用的方法——真心觉得比java，c好用

    # Strings have many methods wo can use rand_string=" life is a beautiful struggle " print( ...

  2. Python语言学习：字符串常用的方法

    python字符串常用的方法 1. find( ):在字符串中搜索指定的值并返回它被找到的位置,如果没有找到,则返回-1 string.find(value,start,end) #value:必需, ...

  3. python字符串常用内置方法

    python字符串常用内置方法 定义: 字符串是一个有序的字符的集合,用与存储和表示基本的文本信息. python中引号中间包含的就是字符串. # s1='hello world' # s2=&quo ...

  4. python字符串操作实方法大合集

    python字符串操作实方法大合集,包括了几乎所有常用的python字符串操作,如字符串的替换.删除.截取.复制.连接.比较.查找.分割等,需要的朋友可以参考下:   #1.去空格及特殊符号 s.st ...

  5. python 字符串常用操作方法

    python 字符串常用操作方法 python 字符串操作常用操作,如字符串的替换.删除.截取.赋值.连接.比较.查找.分割等 1.去除空格 str.strip():删除字符串两边的指定字符,括号的写 ...

  6. python3【基础】-字符串 常用的方法

    字符串一个最重要的特性就是不可修改. name.capitalize() 首字母大写 name.casefold() 大写全部变小写 name.center(50,"-") 输出 ...

  7. Python—字符串常用函数

    Python-字符串常用字符串 字符串是一种表示文本的数据类型,使用单引号和双引号及三引号表示 访问字符串中的值字符串的每个字符都对应一个下标,下标编号是从0开始 转义字符字符串的格式化输出切片常用函 ...

  8. python字符串常用操作方法

    python字符串操作常用操作,如字符串的替换.删除.截取.复制.连接.比较.查找.分割等,需要的朋友可以参考下. 1.去除空格str.strip():删除字符串两边的指定字符,括号的写入指定字符,默 ...

  9. Python 字符串格式化操作 - format方法

    建议使用format()方法 字符串操作 对于 %, 官方以及给出这种格式化操作已经过时,在 Python 的未来版本中可能会消失. 在新代码中使用新的字符串格式.因此推荐大家使用format()来替 ...

随机推荐

  1. 关于JS中变量提升的规则和原理的一点理解（二）

    上篇文章中讲到变量提升和函数提升的先后顺序时蒙了,后来去查了一下资料,特别整理一下. 在<你不知道的JavaScript(上卷)>一书的第40页中写到:函数会首先被提升,然后才是变量. 书 ...

  2. linux（三）之linux常用命令二

    今天就是星期五了,又可以休息两天了.有点小激动,开心.不过还是要加油,因为还有很多东西等着我去学习呢! 七.chmod 作用:修改文件的权限 7.1.命令格式:chmod mode filename ...

  3. 【Java学习笔记之十四】Java中this用法小节

    用类名定义一个变量的时候,定义的只是一个引用,外面可以通过这个引用来访问这个类里面的属性和方法. 那们类里面是够也应该有一个引用来访问自己的属性和方法纳? 呵呵,JAVA提供了一个很好的东西,就是 t ...

  4. 【Java学习笔记之十二】Java8增强的工具类：Arrays的用法整理总结

    本文将整理 java.util.Arrays 工具类比较常用的方法:  本文介绍的方法基于JDK 1.7 之上.  1.  asList方法 @SafeVarargs public static &l ...

  5. NYoj_104最大和

    最大和 时间限制:1000 ms  |  内存限制:65535 KB 难度:5 描述 给定一个由整数组成二维矩阵(r*c),现在需要找出它的一个子矩阵,使得这个子矩阵内的所有元素之和最大,并把这个子矩 ...

  6. JAVA爬虫实践（实践三：爬虫框架webMagic和csdnBlog爬虫）

    WebMagic WebMagic是一个简单灵活的Java爬虫框架.基于WebMagic,你可以快速开发出一个高效.易维护的爬虫. 采用HttpClient可以实现定向的爬虫,也可以自己编写算法逻辑来 ...

  7. Linux学习之XShell与虚拟机的连接

    最近在慕课网上学习Linux视频,记录一下解决问题的方法和过程. 实验软件环境: 虚拟机软件Vmware Workstation10.0.虚拟机系统CentOS 6.3(32位).XShell 5.0 ...

  8. Generator函数异步应用

    转载请注明出处: Generator函数异步应用 上一篇文章详细的介绍了Generator函数的语法,这篇文章来说一下如何使用Generator函数来实现异步编程. 或许用Generator函数来实现 ...

  9. 如何让低版本IE浏览器支持HTML5标签并为其设置样式

    现代的浏览器都支持HTML5,HTML5定义了 8 个新的 HTML 语义元素.所有这些元素都是 块级 元素. 为了能让旧版本的浏览器正确显示这些元素,你可以设置 CSS 的 display 属性值为 ...

  10. vuethink 配置

    http://blog.csdn.net/hero82748274/article/details/76100938 vuethink 是一款基于PHP TP5和Vuejs 结合的后台框架,设计起来是 ...