#Python's usage of regular expressions

In Python, regular expressions are used via the re module. Since regular expressions have their own escape syntax, it’s common to use Python raw strings to avoid double escaping.

Function	Description	Example
match	Checks if the string matches the pattern from the beginning	See below
search	Searches for a substring matching the pattern	See below
sub	Replaces substrings that match the pattern	See below
split	Splits string using substrings that match the pattern	See below
compile	Compiles a pattern for reuse	See below

#Pattern Matching

import re

# Validate email format
email_pattern = r'^[a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+\.[a-zA-Z0-9-.]+$'
if re.match(email_pattern, "[email protected]"):
    print("Valid email")
>>> Establishing WebAssembly Runtime. 
>>> Standby. 
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#Text Search

import re

text = "Order ID: 12345, Date: 2023-08-15"
match = re.search(r'Order ID: (\d+), Date: (\d{4}-\d{2}-\d{2})', text)
if match:
    print(0, match.group(0))
    print(1, match.group(1))
    print(2, match.group(2))
>>> Establishing WebAssembly Runtime. 
>>> Standby. 
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#Text Replacement

import re

text = "Username: user Password: 123456"
hidden = re.sub(r'\d{6}', '******', text)
print(hidden)
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>>> Standby. 
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#Text Splitting

import re

data = "Apple, Banana, Orange, Grape"
fruits = re.split(r',\s*', data)  # Split by comma, allowing optional space after
print(fruits)  # Output: ['Apple', 'Banana', 'Orange', 'Grape']
>>> Establishing WebAssembly Runtime. 
>>> Standby. 
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#Compiling Regular Expressions

Compiling a pattern improves efficiency when used multiple times.

import re

# Compile email pattern
email_pattern = re.compile(r'^[a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+\.[a-zA-Z0-9-.]+$')
if email_pattern.match("[email protected]"):
    print("Valid email")
>>> Establishing WebAssembly Runtime. 
>>> Standby. 
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