# 正则表达式：由一系列特殊字符拼接而成的表达式/规则，该表达式用于从一个大字符串中匹配出符合规则的子字符串
import re
#1、w 数字 字母 下划线
# print(re.findall('www',"h ello 123_ (0"))
# ['ell', '123']
#2、 W 非 数字 字母 下划线
# print(re.findall('W',"h ello 123_ (0"))
# [' ', ' ', ' ', '(']
#3、s 空白
# print(re.findall('s',"h e ll
o 123_ (0"))
# [' ', ' ', '
', ' ', ' ']
# print(re.findall('ws',"h ello 123_ (0"))
# ['h ', 'o ', '_ ']
#4、S 非 空白
# print(re.findall('S',"h e ll
o 123_ (0"))
# ['h', 'e', 'l', 'l', 'o', '1', '2', '3', '_', '(', '0']
#5、d 数字
# print(re.findall('d',"h e ll
o 123_ (0"))
# ['1', '2', '3', '0']
#6、D 非 数字
# print(re.findall('D',"h e ll
o 123_ (0"))
# ['h', ' ', 'e', ' ', 'l', 'l', '
', 'o', ' ', '_', ' ', '(']
# print(re.findall("adb","a1b a2b a b aab aaaaaaaa1b a2c a22c a 3c"))
# ['a1b', 'a2b', 'a1b']
#7、
与
# msg="""h e ll
o 123_ (0
# 1
# 2
# 3
# """
# print(re.findall('
',msg))
# ['
', '
', '
', '
', '
', '
'] # 换行符
# print(re.findall(' ',msg))
# [' ', ' '] # 制表符
# print(re.findall(' ',msg))
# [' ', ' ', ' ', ' ', ' ', ' ', ' '] # 空白符
#8、^与$
# print(re.findall("^egon","egon asdf 213123 egonafsadfegon"))
# ['egon']
#
# print(re.findall("egon$","egon asdf 213123 egonafsadfegon "))
# []
#
# print(re.findall("awwwc","ab12c3c a213c"))
# ['ab12c', 'a213c']
#
# print(re.findall("^awwwc$","ab_2c"))
# ['ab_2c']
#9、.与[]
#9.1 .：代表匹配一个字符，该字符可以是任意字符
# print(re.findall("adb","a1b a2b aab aaaaaaab a+b a-b a c"))
# ['a1b', 'a2b']
# print(re.findall("awb","a1b a2b aab aaaaaaab a+b a-b a c"))
# ['a1b', 'a2b', 'aab', 'aab']
# print(re.findall("a.b","a1b a2b aab aaaaaaab a+b a-b a b a c"))
# ['a1b', 'a2b', 'aab', 'aab', 'a+b', 'a-b', 'a b']
# print(re.findall("a.b","a1b a2b aab aaaaaaab a b a-b a
b a c",re.DOTALL))
# ['a1b', 'a2b', 'aab', 'aab', 'a b', 'a-b', 'a
b']
#9.2 []：代表匹配一个字符，我们可以指定该字符的范围
# print(re.findall("a[+-]b", "a1b a2b aab aaaaaaab a+b a-b a c"))
# ['a+b', 'a-b']
# print(re.findall("a[.*/+-]b", "a.b a2b a*b a/b aab aaaaaaab a+b a-b a c"))
# ['a.b', 'a*b', 'a/b', 'a+b', 'a-b']
# print(re.findall("a[a-z]b", "a.b a2b a*b a/b aab aaaaaaab a+b a-b a c")) # -放在[]内的开头或结果
# ['aab', 'aab']
# print(re.findall("a[a-zA-Z]b", "a.b a2b a*b a/b aAb aCb aab aaaaaaab a+b a-b a c")) # -放在[]内的开头或结果
# ['aAb', 'aCb', 'aab', 'aab']
# print(re.findall("adb", "a.b a2b a*b a/b aAb aCb aab aaaaaaab a+b a-b a c")) # -放在[]内的开头或结果
# ['a2b']
# print(re.findall("a[0-9]b", "a.b a2b a*b a/b aAb aCb aab aaaaaaab a+b a-b a c")) # -放在[]内的开头或结果
# ['a2b']
# [^...]代表取反
# print(re.findall("a[^0-9]b", "a.b a2b a*b a/b aAb aCb aab aaaaaaab a+b a-b a c")) # -放在[]内的开头或结果
# ['a.b', 'a*b', 'a/b', 'aAb', 'aCb', 'aab', 'aab', 'a+b', 'a-b']
#9.3 *: 左边那个字符出现0次或者无穷次
# print(re.findall("ab*","a ab abb abbbbbbbbbbbb bbbbbbbbb"))
# ['a', 'ab', 'abb', 'abbbbbbbbbbbb']
#9.4 +: 左边那个字符出现1次或者无穷次
# print(re.findall("ab+","a ab abb abbbbbbbbbbbb bbbbbbbbb"))
# ['ab', 'abb', 'abbbbbbbbbbbb']
#9.5 {n,m}: 左边那个字符出现n次到m次
# print(re.findall("ab{0,}","a ab abb abbbbbbbbbbbb bbbbbbbbb"))
# ['a', 'ab', 'abb', 'abbbbbbbbbbbb']
# print(re.findall("ab*","a ab abb abbbbbbbbbbbb bbbbbbbbb"))
# ['a', 'ab', 'abb', 'abbbbbbbbbbbb']
# print(re.findall("ab{1,}","a ab abb abbbbbbbbbbbb bbbbbbbbb"))
# ['ab', 'abb', 'abbbbbbbbbbbb']
# print(re.findall("ab+","a ab abb abbbbbbbbbbbb bbbbbbbbb"))
# ['ab', 'abb', 'abbbbbbbbbbbb']
# print(re.findall("ab{2,5}","a ab abb abbb abbbb abbbbbbbb abbbbbbbbbbbb bbbbbbbbb"))
# ['abb', 'abbb', 'abbbb', 'abbbbb', 'abbbbb']
#9.6 ?: 左边那个字符出现0次到1次
# print(re.findall("ab?","a ab abb abbbbbbbbbbbb bbbbbbbbb"))
# ['a', 'ab', 'ab', 'ab']
#9.7 .*: 匹配所有
# print(re.findall("a.*b","123 a1231-==-000b123123123123123b"))
# ['a1231-==-000b123123123123123b']
#
# print(re.findall("a.*?b","123 a1231-==-000b123123123123123b"))
# ['a1231-==-000b']