正则表达式之 match ， findall， sub，subn

 #正则表达式之 match以及分组
 import re
 #无分组
 origin = "hello alex bcd alex lge alex avd 19"
 r = re.match ("h\w+",origin)
 print(r.group())      #获取匹配到的所有结果
 print(r.groups())     #获取模型中匹配到的分组结果
 print(r.groupdict())  #获取模型中匹配的分组结果
 hello
 ()
 {}

 #有分组
 #为何要有分组？ 提取匹配成功的制定内容(先欧赔成功全部正则，在再匹配成功的局部内容提取出来)

 origin = "hello alex bcd alex lge alex avd 19"
 r = re.match("(?P<n1>h)(?P<n2>\w+)",origin)
 print(r.group())      #获取匹配到的所有结果
 print(r.groups())     #获取模型中匹配到的分组结果
 print(r.groupdict())  #获取模型中匹配到的分组中所有执行了key的组
 hello
 ('h', 'ello')
 {'n1': 'h', 'n2': 'ello'}

 --------------------------------------------------------------------------------------------------------------
 #正则表达式之findall
 import re

 origin = "hello alex alex bcd abcd lge acd 19"
 r = re.findall("(a)(\w+)(x)",origin)
 print(r)
 [("a","le","x"),("a","le","x")]

 a = "alex"
 n = re.findall("(\w)(\w)(\w)(\w)",a)
 print(n)
 [('a', 'l', 'e', 'x')]

 n = re.findall("(\w)*",a)
 print(n)
 ['x', '']

 n =re.findall("","abcd")
 print(n)
 ['', '', '', '', '']

 -----------------------------------------
 #正则表达式之sub，subn
 import re
 origin = "1fsdfsd234sdfsdfdfgrm456gfhkbss34"
 new_str = re.sub("\d+","kkk",origin)
 print(new_str)
 kkkfsdfsdkkksdfsdfdfgrmkkkgfhkbsskkk

 origin ="1fdfsffsd234gdsgertsg456gsfsf34"
 new_str,count = re.subn("\d+","kkk",origin)
 print(new_str,count)
 ('kkkfdfsffsdkkkgdsgertsgkkkgsfsfkkk', 4)