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How to Mask Credit Card Middle Digits in Python

Mask the middle digits of credit card numbers in a string, keeping only the first 8 and last 4 digits, using regular expressions.

regex string-manipulation security

Python

import re

def mask_credit_card(text: str) -> str:
    pattern = re.compile(r'(\d{4}[-\s]?)(\d{4}[-\s]?)(\d{4}[-\s]?)(\d{4})')
    return pattern.sub(lambda m: m.group(1) + m.group(2) + '****' + m.group(4), text)

if __name__ == "__main__":
    sample = "Card: 1234-5678-9012-3456 and 1111 2222 3333 4444"
    print(mas…

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