Python Regular expression (3)--match method

1.re.match function

Re.match attempts to match a pattern from the starting position of the string, and if the match is not successful, match () returns none.

(1) function Syntax：

Re.  Match(pattern,string, flags=0)       

Function parameter Description:

Pattern-matched Regular expression

String to match

Flgs flag bit, used to control how regular expressions are matched

We can use the group (NUM) or groups () matching object function to get a matching expression.

Group (num=0) gets a string of individual groupings that match the result, and group () can enter multiple group numbers at a time, returning a tuple that contains the corresponding values for those groups.

Groups () returns a tuple that contains all the grouped strings.

Note: If the mismatch succeeds, thematch() return value is None, and the group (), groups () method is used at this time to give an error.

You should get the matching object first, and then determine if the matching object is not empty, and use the group (), groups () method to get the matching result when not empty. See Example 2

(2) Example 1Import Re
Print(Re.Match(‘How‘,‘How is You‘ . Span)   # in the starting position match
    Print (re. Match ( ' are Span class= "Hl-code", "how is You ) )                # does not match the starting position

The above output results are:

  (0,3)None    

Example 2Import re content = ' 577 Zeke 'result = Re.match (R ' [a-z]\d ', content ')If result:print Result.group ()Else:print ' No match! '

The results of the above execution are as follows:
/span>

No match!

2.pattern.match method (1) Function syntax

Pattern. Match( string, pos=0, Endpos=len (String))

Function Effect:

This method will attempt to match pattern at the POS position of string strings (the pattern is the object returned after compiling through the Re.compile () method), if the pattern match succeeds, regardless of whether the end position is reached Endpos, will return a match object that matches successfully;

If the match is unsuccessful, or if the pattern does not match the end to reach Endpos, None is returned.

Function parameter Description:

String: strings that are matched

POS: The starting position of the match, optional, default is 0

Endpos: Match end position, optional, Len (string) by default

3. Re.match and Pattern.match differences

The Re.match method differs from the Pattern.match () method in that it cannot specify two parameters for a matched interval pos and Endpos

Python Regular expression (3)--match method