re.MatchObject.groups() function in Python - Regex

Last Updated : 29 Aug, 2020

This method returns a tuple of all matched subgroups.

Syntax: re.MatchObject.groups()

Return: A tuple of all matched subgroups

AttributeError: If a matching pattern is not found then it raise AttributeError.

Consider the below example:

Example 1:

Python3

import re

"""We create a re.MatchObject and store it in 
   match_object variable
   the '()' parenthesis are used to define a 
   specific group"""

match_object = re.match(r'(\d+)\-(\w+)\-(\w+)',
                        '498-ImperialCollege-London')

""" d in above pattern stands for numerical character
    w in above pattern stands for alphabetical character
    + is used to match a consecutive set of characters 
    satisfying a given condition so w+ will match a
    consecutive set of alphabetical characters
    d+ will match a consecutive set of numerical characters
    """

# generating the tuple with all matched groups
detail_tuple = match_object.groups()

# printing the tuple
print(detail_tuple)

Output:

('498', 'ImperialCollege', 'London')

It's time to understand the above program. We use a re.match() method to find a match in the given string('498-ImperialCollege-London') the 'w' indicates that we are searching for a alphabetical character and the '+' indicates that we are searching for continuous alphabetical characters in the given string. Similarly d+ will match a consecutive set of numerical characters.Note the use of '()' the parenthesis is used to define different subgroups, in the above example we have three subgroups in the match pattern.The result we get is a re.MatchObject which is stored in match_object variable.

Example 2: If a match object is not found then it raises AttributeError.

Python3

import re

"""We create a re.MatchObject and store it in 
   match_object variable
   the '()' parenthesis are used to define a 
   specific group"""

match_object = re.match(r'(\d+)\-(\w+)\-(\w+)', 
                        '1273984579846')

""" w in above pattern stands for alphabetical character
    + is used to match a consecutive set of characters 
    satisfying a given condition so 'w+' will match a
    consecutive set of alphabetical characters
    """

# Following line will raise AttributeError exception
print(match_object.groups())

Output:

Traceback (most recent call last):
  File "/home/6510bd3e713a7b9a5629b30325c8a821.py", line 18, in 
    print(match_object.groups())
AttributeError: 'NoneType' object has no attribute 'groups'