Python | Extract substrings between brackets

Last Updated : 22 Apr, 2020

Sometimes, while working with Python strings, we can have a problem in which we need to extract the substrings between certain characters and can be brackets. This can have application in cases we have tuples embedded in string. Lets discuss certain ways in which this task can be performed.

Method #1 : Using regex
One way to solve this problem is by using regex. In this we employ suitable regex and perform the task of extraction of required elements.

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# Python3 code to demonstrate working of 
# Extract substrings between brackets
# Using regex
import re
  
# initializing string
test_str = "geeks(for)geeks is (best)"
  
# printing original string
print("The original string is : " + test_str)
  
# Extract substrings between brackets
# Using regex
res = re.findall(r'\(.*?\)', test_str)
  
# printing result 
print("The element between brackets : " + str(res)) 

Output :

The original string is : geeks(for)geeks is (best)
The element between brackets : ['(for)', '(best)']

Method #2 : Using list comprehension + isintance() + eval()
The combination of above methods can also be used to solve this problem. In this eval() assume the brackets to be tuples and helps the extraction of strings within them.

# Python3 code to demonstrate working of 
# Extract substrings between brackets
# Using list comprehension + eval() + isinstance()
  
# initializing string
test_str = "[(234, ), 4, (432, )]"
  
# printing original string
print("The original string is : " + test_str)
  
# Extract substrings between brackets
# Using list comprehension + eval() + isinstance()
res = [str(idx) for idx in eval(test_str) if isinstance(idx, tuple)]
  
# printing result 
print("The element between brackets : " + str(res)) 

Output :

The original string is : [(234, ), 4, (432, )]
The element between brackets : ['(234, )', '(432, )']

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Python | Extract substrings between brackets