Commonly used functions and methods of python-re module

Common Regular Expression Properties

• just the re module function

  compile(pattern，flags= 0)

  Compile the regex pattern with any optional tokens, then return a regex object

  
  
  
• re module functions and methods of regular expression objects 

  match(pattern，string，flags=0)	Attempts to match strings using a regular expression pattern with optional tokens. If the match is successful, it returns the match object; if it fails, it returns None
  search(pattern，string，flags=0)	Search for the first occurrence of a regular expression pattern in a string using optional tokens. If the match is successful, it returns the match object; if it fails, it returns None
  findall(pattern，string[, flags] )①	Finds all (non-repeating) occurrences of a regular expression pattern in a string and returns a list of matches
  finditer(pattern，string[, flags] )②	Same as findall() , but instead of returning a list, it returns an iterator. For each match, the iterator returns a match object
  split(pattern，string，max=0)③	According to the pattern separator of the regular expression, the split function splits the string into a list, and then returns a list of successful matches, separated by up to max times (by default, all matching positions are split)

  sub(pattern，repl，string，count=0)③	Use repl to replace all occurrences of the regular expression pattern in the string, unless count is defined , otherwise all occurrences will be replaced (see also the subn() function, which returns the number of replacement operations)
  purge()	Clear implicitly compiled regex patterns

  
  
  
• Commonly used match object methods (check documentation for more info)

  group(num=0)	Returns the entire match object, or a specific subgroup numbered num
  groups(default=None)	Returns a tuple containing all matching subgroups (or an empty tuple if no match was successful)
  groupdict(default=None)	Returns a dictionary containing all matching named subgroups with all subgroup names as dictionary keys (or an empty dictionary if no match was successful)

  
  
• Common module attributes (tags used for most regular expression functions)

  re.I、 re.IGNORECASE	case-insensitive match
  re.L、 re.LOCALE	Matching via \w , \W , \b , \B , \s , \S depending on the locale used
  re.M、 re.MULTILINE	^ and $ match the beginning and end of a line in the target string, respectively, rather than strictly matching the beginning and end of the entire string itself
  re.S、 rer.DOTALL	“.” （点号）通常匹配除了\n（换行符）之外的所有单个字符；该标记表示“.” （点号） 能够匹配全部字符
  re.X、 re.VERBOSE	通过反斜线转义， 否则所有空格加上#（以及在该行中所有后续文字）都被忽略，除非 在一个字符类中或者允许注释并且提高可读性

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