How to return string representation of re.search() in python

Question

I am aware that [re.search(pattns,text)][1] in python method takes a regular expression pattern and a string and searches for that pattern within the string. If the search is successful, search() returns a match object or None otherwise.

My problem however is, am trying to implement this using OOP (class) i want to return a string representation of the results of the matches whether true or none or any other form of representation(readable) not this <__main__.Expression instance at 0x7f30d0a81440> below are two example classes : Student and Epression. The one using __str__(self)__ works fine but i cannot figure out how to get the representation funtion for re.search(). Please someone help me out.

import re   

class Expression:
    def __init__(self,patterns,text):

        self.patterns = patterns
        self.text = text


    def __bool__(self):
    # i want to get a readable representation from here
        for pattern in self.patterns:
           result = re.search(pattern,self.text)
           return result



 patterns = ['term1','term2','23','ghghg']
 text = 'This is a string with term1 23 not ghghg the other'

 reg = Expression(patterns,text)
 print(reg)


 class Student:

    def __init__(self, name):

       self.name = name


   def __str__(self):
    # string representation here works fine
        result = self.name 
        return result

 # Usage:

  s1 = Student('john')
  print(s1)


 [1]: https://developers.google.com/edu/python/regular-expressions

Answer 1

The output of re.search returns a match object. It tells you whether the regex matches the string.

You should identify the group to retrieve string from the match like so:

if result: 
    return result.group(0)

Replace return result in your code with above code snippet.

If you are not sure how group works, here is an example from docs:

>>> m = re.match(r"(\w+) (\w+)", "Isaac Newton, physicist") 
>>> m.group(0) # The entire match 
'Isaac Newton' 
>>> m.group(1) # The first parenthesized subgroup. 
'Isaac' 
>>> m.group(2) # The second parenthesized subgroup. 
'Newton' 
>>> m.group(1, 2) # Multiple arguments give us a tuple. 
('Isaac', 'Newton')