Sometimes it becomes tough to remove brackets from the text file which is unnecessary to us. Hence, python can do this for us. In python, we can remove brackets with the help of regular expressions.
Syntax:
# import re module for using regular expression
import re
patn = re.sub(pattern, repl, sentence)
# pattern is the special RE expression for finding the brackets.
# repl is a string which replaces with the selected things by pattern
# RE is searched in sentence string
The regex pattern used for performing our task:
Note: Here, we have used 2 syntactic characters of regex for doing this-
- […] is a character class that is used to match any one of the characters presents between them
- \ is used for matching the special characters for this, we have brackets as a special character
Here is how it works:
Example 1: Program for removing the brackets with regular expressions from the string
Python3
# importing re module for creating# regex expressionimport re# string for passingtext = "Welcome to Lazyroar for Lazyroar [GFG] A (computer science portal)"# creating the regex pattern & use re.sub()# [\([{})\]] is a RE pattern for selecting# '{', '}', '[', ']', '(', ')' brackets.patn = re.sub(r"[\([{})\]]", "", text)print(patn) |
Output:
Welcome to Lazyroar for Lazyroar GFG A computer science portal
Now seems like our script is working well. Let’s try the same in a text file. Python enables us to handle files.
Note: For more information, refer File handling in Python.
Example 2: Program for removing brackets from the text file
File Used:
Python3
# importing re module for creating# regex expressionimport re# reading line by linewith open('data.txt', 'r') as f: # looping the para and iterating # each line text = f.read() # getting the pattern for [],(),{} # brackets and replace them to empty # string # creating the regex pattern & use re.sub() patn = re.sub(r"[\([{})\]]", "", text)print(patn) |
Output:
Example 2: Appending the changes to a new text file
File Used:
Python3
# importing re module for creating# regex expressionimport re# reading line by linewith open('input.txt', 'r') as f: # store in text variable text = f.read() # getting the pattern for [],(),{} # brackets and replace them to empty string # creating the regex pattern & use re.sub() pattern = re.sub(r"[\([{})\]]", "", text)# Appending the changes in new file# It will create new file in the directory# and write the changes in the file.with open('output.txt', 'w') as my_file: my_file.write(pattern) |
Output:
