Password entropy example

password_entropy.py

import re
from math import log,pow

class PasswordStrength:
    def __init__(self):
        self.numeric=re.compile('\d')
        self.loweralpha=re.compile('[a-z]')
        self.upperalpha=re.compile('[A-Z]')
        self.symbols=re.compile('[-_.:,;<>?"#$%&/()!@~]')
        self.num_of_symbols=20 # adjust accordingly...

    def calculate_entropy(self,password=''):
        charset = 0
        if self.numeric.search(password):
            charset += 10
        if self.loweralpha.search(password):
            charset += 26
        if self.upperalpha.search(password):
            charset += 26
        if self.symbols.search(password):
            charset += self.num_of_symbols
        entropy = log(pow(charset,len(password)),2)
        return entropy