Get the optimal password length from charset.

get_optimal_password_length.py

from math import log

DEFAULT_CHARSET = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890!§$%&/()=?+*#-_.:,;<>"

Entropie = lambda p: - sum([i * log(i, 2) for i in p])

charset = input(f"Charset [{DEFAULT_CHARSET}]: ")
if charset in (None, "", " "):
    charset = DEFAULT_CHARSET

charset_length = len(charset)
p = 1 / charset_length
e = Entropie([p for i in range(charset_length)])
print("Optimal password length:", int(100 / e) + 1)