Regular Expressions(RegEx) in Python: Key Functions and Examples

 Regular Expressions (RegEx) in Python :

• A regular expression (RegEx) is a sequence of characters that defines a search pattern. It is used for pattern matching within strings, such as searching, replacing, or extracting information. Python provides the re module to work with regular expressions.

Key Functions in Python's re module:

import re  # Import the 're' module to work with regular expressions.

1. re.match() - 

• Matches the pattern at the beginning of the string.

 

2. re.search() - 

• Searches for the pattern anywhere in the string.

3. re.findall() - 

• Finds all occurrences of the pattern in the string.

4. re.sub() - 

• Replaces occurrences of the pattern with a specified string.

5. re.split() -

• Splits the string at occurrences of the pattern.

Example of special characters in a pattern:

`.`: Matches any character except a newline.

`^`: Matches the start of the string.

`$`: Matches the end of the string.

`[]`: Matches any character inside the brackets.

`|`: Acts as an OR operator in patterns.

`*`, `+`, `?`: Quantifiers for repetition (zero or more, one or more, zero or one).

 `()` groups patterns.

Program: