Python basic eleventh day -re module

reModular

common method

• findall()

  Returns all eligible results in a list.

  

  1 import  re
  2 print(re.findall('\d','a1b2c2abc123'))#['1', '2', '2', '1', '2', '3']

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• search()

  Finding the first matching information returns an object containing matching information (returning None if not found), which looks at the result through the group () function

  

  1 import re
  2 
  3 str = 'a1b2c2abc123'
  4 print(re.search('\d', str).group())  # 1

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• match()

  Starting from string, location matching, others with search ()

  

  1 import re
  2 
  3 str = 'a1b2c2abc123'
  4 print(re.match('\d', str).group() if re.match('\d', str) else 'not found')  # not found
  5 print(re.match('a.+', str).group() if re.match('a', str) else 'not found')  # a1b2c2abc123

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• split()

  Cuts the string with regular matching characters, and returns the list of cut strings.

  

  1 import re
  2 
  3 str = 'a1b2c2abc123'
  4 print(re.split('[123]', str))  # ['a', 'b', 'c', 'abc', '', '', '']

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• sub()

  Replace the matching content with the specified content and return the replaced string ().

  

  1 import re
  2 
  3 str = 'a1b2c2abc123'
  4 print(re.sub('[123]', 'A', str))  # aAbAcAabcAAA

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• subn()

  Replaces the matched content with the specified content and returns the meta-ancestor. The first value is the substituted string, and the second value is the number of substitutions.

  

  1 import re
  2 
  3 str = 'a1b2c2abc123'
  4 print(re.subn('[123]', 'A', str))  # ('aAbAcAabcAAA', 6)

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• compile()

  Compiles regular expressions into bytecode objects, which can be called multiple times.

  

   1 import re
   2 
   3 str = 'a1b2c2abc123'
   4 re_obj = re.compile('[123]')
   5 print(re_obj.sub('A', str))  # aAbAcAabcAAA
   6 print(re_obj.subn('A', str))  # ('aAbAcAabcAAA', 6)
   7 print(re_obj.findall(str))  # ['1', '2', '2', '1', '2', '3']
   8 print(re_obj.split(str))  # ['a', 'b', 'c', 'abc', '', '', '']
   9 print(re_obj.match(str))  # None
  10 print(re_obj.search(str).group())  # 1

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• finditer()

  Returns an iterator that matches the result.

  

  1 import re
  2 
  3 str = 'a1b2c2abc123'
  4 result = re.finditer('\d', str)
  5 print(result)  # <callable_iterator object at 0x00000000026F80F0>
  6 print(next(result).group())  # 1
  7 print(next(result).group())  # 2
  8 print([g.group() for g in result])  # ['2', '1', '2', '3']

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Priority problem

• findall()

  findallThe result of group matching results is preferentially returned.

  ?: You can cancel the matching result of priority return group.

  

  1 import re
  2 
  3 print(re.findall('zz([a-y])', 'zze'))  # ['e']
  4 print(re.findall('zz(?:[a-y])', 'zze'))  # ['zze']

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• split()

  When regular inclusion groups are set, the segmentation result is preserved.

  

  1 import re
  2 
  3 str = 'a1b2c2abc123'
  4 print(re.split('\d', str))  # ['a', 'b', 'c', 'abc', '', '', '']
  5 print(re.split('(\d)', str))  # ['a', '1', 'b', '2', 'c', '2', 'abc', '1', '', '2', '', '3', '']

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extend

• Group naming

  Can be named by group P’?

  

  1 import re
  2 
  3 str = '<title>python learning</title>'
  4 result = re.search('<(?P<tag_name>[a-z]+)>(?P<title>.+)</([a-z]+)>', str)
  5 print(result.group('title'))  # python learning
  6 print(result.group('tag_name'))  # title
  7 print(result.group())  # <title>python learning</title>

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