line = "This is my love!"

 fields = line.split(' ')

 print(fields)

 # ['This', 'is', 'my', 'love!']

 # 多条件分割

 import re

 line = "asd dfwerf, sdfs; jtyy. werwe, sdfsd"

 fields = re.split(r"(,|\.|;|\s)\s*", line)

 print(fields)

 # ['asd', ' ', 'dfwerf', ',', 'sdfs', ';', 'jtyy', '.', 'werwe', ',', 'sdfsd']

 # 如果不需要分隔符可以使用(?:...)不捕获分组

 fields = re.split(r"(?:,|\.|;|\s)\s*", line)

 print(fields)

 # ['asd', 'dfwerf', 'sdfs', 'jtyy', 'werwe', 'sdfsd']

 url = 'https://www.baidu.com'

 print(url.startswith('https'))

 # True

 words = ['sd', 'asad', 'fgwer', 'jtdwse', 'qwieu', 'pqwej', 'ejwqi', 'iaweq']

 w = [word for word in words if word.startswith(('a', 'e', 'i'))]

 # startswith()，endswith()方法接收一个元组表示多项匹配，元组的括号不可以省略

 print(w)

 # ['asad', 'ejwqi', 'iaweq']

 # 判断某个目录下是否有某些类型的文件

 if any(name.endswith(('.c', '.h')) for name in listdir(dirname)):

     pass

 from fnmatch import fnmatch, fnmatchcase

 print(fnmatch('hello.py', '*.py'))

 # True

 print(fnmatch('hello.py', '?ello.py'))

 # True

 print(fnmatch('hello-1.py', 'hello-[0-9].py'))

 # True

 print(fnmatch('hello.txt', '*.TXT'))

 # fnmatch()在不同操作系统中结果不同

 # 若在类UNIX系统中为False(即大小写敏感)，在Windows系统中为True(即大小写不敏感)

 print(fnmatchcase('hello.txt', '*.TXT'))

 # False

 # fnmatchcase()在任何操作系统中都大小写敏感

 import re

 date = '7/24/2018'

 # 匹配

 print(bool(re.match(r'\d+/\d+/\d+', date)))

 # True

 # 同一模式多次使用可以预先编译

 date_pat = re.compile(r'\d+/\d+/\d+')

 print(bool(date_pat.match(date)))

 # True

 # 查找并捕获

 date_pat = re.compile(r'(\d+)/(\d+)/(\d+)')

 line = "Today is 7/24/2018, tomorrow is 7/25/2018"

 print(date_pat.findall(line))

 # [('7', '24', '2018'), ('7', '25', '2018')]

 m = date_pat.match(date)

 print(m)

 print(m.group())

 # 7/24/2018

 print(m.group(1))

 #

 print(m.group(2))

 #

 print(m.group(3))

 #

 print(m.group(0))

 # 7/24/2018

 line = "Yes, it's me!"

 print(line.replace("Yes", "Yeah"))

 # Yeah, it's me!

 import re

 text = "Today is 7/24/2018, tomorrow is 7/25/2018"

 date_pat = re.compile(r'(\d+)/(\d+)/(\d+)')

 print(date_pat.sub(r'\3-\1-\2', text))   # 其中r'\3-\1-\2'指的是通过正则捕获的数据的索引，和上面group()方法的对应关系相同

 # Today is 2018-7-24, tomorrow is 2018-7-25

 # sub()方法还可以接受一个函数作为参数以应对更加复杂的替换

 from calendar import month_abbr

 def change_date(m):  # 参数为match对象，即match()或者find()方法的返回值

     mon_name = month_abbr[int(m.group(1))]

     return "{} {} {}".format(m.group(2), mon_name, m.group(3))

 print(date_pat.sub(change_date, text))

 # Today is 24 Jul 2018, tomorrow is 25 Jul 2018

 # 查看subn()替换的数量

 print(date_pat.subn(change_date, text)) # 返回一个元组，第二个值为替换的次数

 # ('Today is 24 Jul 2018, tomorrow is 25 Jul 2018', 2)

 import re

 text = "UPPER PYTHON, lower python, Mixed Python"

 print(re.findall('python', text, flags=re.IGNORECASE))

 # ['PYTHON', 'python', 'Python']

 print(re.sub('python', 'java', text, flags=re.IGNORECASE))  # 替换并不会按照原有规则，而是所有匹配项都同一替换

 # UPPER java, lower java, Mixed java

 # 可以使用辅助函数弥补

 def matchcase(word):

     def replace(m): # 参数为一个match对象

         text = m.group()

         if text.isupper():

             return word.upper()

         if text.islower():

             return word.lower()

         if text[0].isupper(): # 首字母大写

             return word.title()

         return word

     return replace

 print(re.sub('python', matchcase('java'), text, flags=re.IGNORECASE))

 # UPPER JAVA, lower java, Mixed Java

 import re

 text = 'You said "Yes", I said "No"'

 print(re.findall(r'\".*\"', text))  # 贪婪匹配，匹配结果尽可能长

 # ['"Yes", I said "No"']

 print(re.findall(r'\".*?\"', text)) # 最短匹配， 匹配结果尽可能短

 # ['"Yes"', '"No"']

 import re

 comment = re.compile(r'/\*(.*?)\*/')    # 此模式无法匹配多行, 因为 . 号无法匹配换行符

 text1 = "/* this is a comment */"

 text2 = """

     /* this is a

     multiline comment */

 """

 print(comment.findall(text1))

 # [' this is a comment ']

 print(comment.findall(text2))

 # []

 comment = re.compile(r'/\*((?:.|\n)*?)\*/') # 在模式中加上换行符，可以匹配多行

 print(comment.findall(text1))

 print(comment.findall(text2))

 # [' this is a\n    multiline comment ']

 comment = re.compile(r'/\*(.*?)\*/', flags=re.DOTALL) # flags=re.DOTALL使 . 号可以匹配所有字符

 print(comment.findall(text1))

 # [' this is a comment ']

 print(comment.findall(text2))

 # [' this is a\n    multiline comment ']

 text = "---Hello   World+++"

 print(text.strip("-+")) # 参数默认为 ‘ ’ 空格， 只能清除两侧的多余内容，字符串中间的内容无法清除

 # Hello   World

 print(text.lstrip("-")) # 清除左侧多余字符

 # Hello   World+++

 print(text.rstrip("+")) # 清除右侧多余字符

 # ---Hello   World

 text = "Hello  World"

 print(text.replace('  ', ' ')) # 只能清除/替换固定个数的字符

 # Hello World

 import re

 text = "Hello     World"

 print(re.sub('\s+', ' ', text))  # 可以清除/替换不定个数的字符

 # Hello World

 text = "Hello World"

 print(text.ljust(20, '-')) #v 第一个参数为总字符数， 第二个参数为填充字符，默认为空格

 # Hello World---------

 print(text.rjust(20))

 #          Hello World

 print(text.center(20, '-'))

 # ----Hello World-----

 print(format(text, '>20'))

 #          Hello World

 print(format(text, '-<20'))

 # Hello World---------

 print(format(text, '+^20'))

 # ++++Hello World+++++

 print(format(3.14159265, '-^10.4f'))  # 格式化数字

 # --3.1416--

 text = 'Hello, {name}!'

 print(text.format(name="Stanley"))

 # Hello, Stanley!

 text = '{name} has {n} message(s).'

 name = "Stanley"

 n = 32

 print(text.format_map(vars())) # 从全局变量中查找相应数据

 # Stanley has 32 message(s).

 class UserInfo:

     def __init__(self, name, n):

         self.name = name

         self.n = n

 a = UserInfo('Stanley', 30)

 print(text.format_map(vars(a))) # 从实例属性中查找数据

 # Stanley has 30 message(s).

 class safesub(dict):

     def __missing__(self, key): # 重写__missing__()方法

         return "{" + key + "}"

 text = '{name} has {n} message(s).'

 name = "Stanley"

 print(text.format_map(safesub(vars())))

 # Stanley has {n} message(s).

 import textwrap

 text = "Python is an interpreted high-level programming language for general-purpose programming. Created by Guido van Rossum and first released in 1991, Python has a design philosophy that emphasizes code readability, notably using significant whitespace. It provides constructs that enable clear programming on both small and large scales. In July 2018, the creator Guido Rossum stepped down as the leader in the language community after 30 years."

 print(textwrap.fill(text, 40))

 """

 Python is an interpreted high-level

 programming language for general-purpose

 programming. Created by Guido van Rossum

 and first released in 1991, Python has a

 design philosophy that emphasizes code

 readability, notably using significant

 whitespace. It provides constructs that

 enable clear programming on both small

 and large scales. In July 2018, the

 creator Guido Rossum stepped down as the

 leader in the language community after

 30 years.

 """

 print(textwrap.fill(text, 80, initial_indent="      "))  # 首行缩进

 """

       Python is an interpreted high-level programming language for general-

 purpose programming. Created by Guido van Rossum and first released in 1991,

 Python has a design philosophy that emphasizes code readability, notably using

 significant whitespace. It provides constructs that enable clear programming on

 both small and large scales. In July 2018, the creator Guido Rossum stepped down

 as the leader in the language community after 30 years.

 """

 print(textwrap.fill(text, 80, subsequent_indent="      "))  # 悬挂缩进

 """

 Python is an interpreted high-level programming language for general-purpose

       programming. Created by Guido van Rossum and first released in 1991,

       Python has a design philosophy that emphasizes code readability, notably

       using significant whitespace. It provides constructs that enable clear

       programming on both small and large scales. In July 2018, the creator

       Guido Rossum stepped down as the leader in the language community after 30

       years.

 """