Password Validation with for loop: Python

Question

I am new to Python and I am trying to create a program to validate passwords using a for loop (I have written one using a while loop already. However it is not working correctly.

Like I said I am very new to Python and code writing. I am finding especially difficult looping through the values of a string (password entered) and resolving how to deal with exceptions (for example, not containing certain characters) This is the code I have written.

import string
import re

print('At least 1 letter between [a-z] and 1 letter between [A-Z]. \nAt least 1 number between [0-9]. \nAt least 1 character from [$#@]. \nMinimum length 6 characters. \nMaximum length 16 characters. \n')

def validate():
    password = input('Enter your password: \n')
    if (len(password) < 8):
        print('Password must be at least 8 characters long')
    elif (len(password) >= 16):
        print('Password must be no more than 16 characteres long')
    for i in password:
        if (i.find(string.ascii_lowercase)):
            print('At least one character must be in the range [a-z]')
        elif (i.find(string.ascii_uppercase)):
            print('At least one character must be in the range [A-Z]')
        elif (i.find(string.digits)):
            print('At least one character must be in range[0-9]')
        elif (re.search('[@,#,$]', password) is None):
            print('At least one of these characters (@ - # -$) must be included')
        else:
            print('your password is good:')
            break
validate()

What is the purpose of the for loop here? i would recommend you really think about the logic of your if/else logic because it will not work. When you do for i in password, you are iterating each character in the password as i. I would highly recommend drawing a flow diagram and working from there. — Jason Chia
– Jason Chia, Commented May 11, 2020 at 11:21
Basically all 4 regexes should match... [a-z]+ [A-Z]+ [0-9]+ [@#$]+ — Rajat Jain
– Rajat Jain, Commented May 11, 2020 at 11:48

Rajat Jain · Accepted Answer · 2020-05-11 11:52:25Z

1

Try this:

import re
if re.search("[a-z]+", password) is None:
    print('At least one character must be in the range [a-z]')

if re.search("[A-Z]+", password) is None:
    print('At least one character must be in the range [A-Z]')

if re.search("[0-9]+", password) is None:
    print('At least one character must be in the range [0-9]')

if re.search("[@#$]+", password) is None:
    print('At least one character must be in the range [a@#$]')

answered May 11, 2020 at 11:52

Rajat Jain

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enriquelc · Accepted Answer · 2020-05-11 12:13:07Z

0

I wanted to use the for loop as an exercise. Just to practise the use of it.

Thanks for the advice. I am very new to all this and I make some very shocking mistakes.

I would still like some pointers about how to iterate through the values of a string and handling the occurrence (or not) of certain characters in that string.

Again, many thanks.

answered May 11, 2020 at 12:13

enriquelc

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