Validation of a Password - Python

Question

So I have to create code that validate whether a password:

Is at least 8 characters long
Contains at least 1 number
Contains at least 1 capital letter

Here is the code:

def validate():
    while True:
        password = input("Enter a password: ")
        if len(password) < 8:
            print("Make sure your password is at lest 8 letters")
        elif not password.isdigit():
            print("Make sure your password has a number in it")
        elif not password.isupper(): 
            print("Make sure your password has a capital letter in it")
        else:
            print("Your password seems fine")
            break

validate()

I'm not sure what is wrong, but when I enter a password that has a number - it keeps telling me that I need a password with a number in it. Any solutions?

Possible duplicate of [check if a string contains a number](http://stackoverflow.com/questions/19859282/check-if-a-string-contains-a-number) — Sayse, Dec 13 '16 at 09:48
Possible duplicate of [Checking the strength of a password (how to check conditions)](http://stackoverflow.com/questions/16709638/checking-the-strength-of-a-password-how-to-check-conditions) — iFlo, Dec 13 '16 at 09:51

score 16 · Accepted Answer · answered Dec 13 '16 at 09:54

You can use re module for regular expressions.

With it your code would look like this:

import re

def validate():
    while True:
        password = raw_input("Enter a password: ")
        if len(password) < 8:
            print("Make sure your password is at lest 8 letters")
        elif re.search('[0-9]',password) is None:
            print("Make sure your password has a number in it")
        elif re.search('[A-Z]',password) is None: 
            print("Make sure your password has a capital letter in it")
        else:
            print("Your password seems fine")
            break

validate()

And for special characters, you can add ``` elif re.search('[^a-zA-Z0-9]',password) is None: print("Make sure your password has a special character in it") ``` — Albert, Jun 13 '22 at 19:18

score 6 · Answer 2 · answered Mar 30 '17 at 07:53

r_p = re.compile('^(?=\S{6,20}$)(?=.*?\d)(?=.*?[a-z])(?=.*?[A-Z])(?=.*?[^A-Za-z\s0-9])')

this code will validate your password with :

min length is 6 and max length is 20
at least include a digit number,
at least a upcase and a lowcase letter
at least a special characters

score 5 · Answer 3 · edited May 23 '17 at 12:10

password.isdigit() does not check if the password contains a digit, it checks all the characters according to:

str.isdigit(): Return true if all characters in the string are digits and there is at least one character, false otherwise.

password.isupper() does not check if the password has a capital in it, it checks all the characters according to:

str.isupper(): Return true if all cased characters in the string are uppercase and there is at least one cased character, false otherwise.

For a solution, please check the question and accepted answer at check if a string contains a number.

You can build your own hasNumbers()-function (Copied from linked question):

def hasNumbers(inputString):
    return any(char.isdigit() for char in inputString)

and a hasUpper()-function:

def hasUpper(inputString):
    return any(char.isupper() for char in inputString)

"`isupper` checks if all the characters in the password is upper". No: ``"HELLO WORLD !!".isupper()` yields `True`. It checks that there's at least an uppercased letter and that no letter is lowercased. — Jean-François Fabre, Dec 13 '16 at 09:59

score 2 · Answer 4 · answered Dec 27 '19 at 13:46

Example:

class Password:
    def __init__(self, password):
        self.password = password

    def validate(self):        
        vals = {
        'Password must contain an uppercase letter.': lambda s: any(x.isupper() for x in s),
        'Password must contain a lowercase letter.': lambda s: any(x.islower() for x in s),
        'Password must contain a digit.': lambda s: any(x.isdigit() for x in s),
        'Password must be at least 8 characters.': lambda s: len(s) >= 8,
        'Password cannot contain white spaces.': lambda s: not any(x.isspace() for x in s)            
        } 
        valid = True  
        for n, val in vals.items():                         
           if not val(self.password):                   
               valid = False
               return n
        return valid                

    def compare(self, password2):
        if self.password == password2:
            return True


if __name__ == '__main__':
    input_password = input('Insert Password: ')
    input_password2 = input('Repeat Password: ')
    p = Password(input_password)
    if p.validate() is True:
        if p.compare(input_password2) is True:
            print('OK')
    else:
       print(p.validate())

srinivasu u · Answer 5 · 2017-11-08T05:29:44.000

You are checking isdigit and isupper methods on the entire password string object not on each character of the string. The following is a function which checks if the password meets your specific requirements. It does not use any regex stuff. It also prints all the defects of the entered password.

#!/usr/bin/python3
def passwd_check(passwd):
    """Check if the password is valid.

    This function checks the following conditions
    if its length is greater than 6 and less than 8
    if it has at least one uppercase letter
    if it has at least one lowercase letter
    if it has at least one numeral
    if it has any of the required special symbols
    """
    SpecialSym=['$','@','#']
    return_val=True
    if len(passwd) < 6:
        print('the length of password should be at least 6 char long')
        return_val=False
    if len(passwd) > 8:
        print('the length of password should be not be greater than 8')
        return_val=False
    if not any(char.isdigit() for char in passwd):
        print('the password should have at least one numeral')
        return_val=False
    if not any(char.isupper() for char in passwd):
        print('the password should have at least one uppercase letter')
        return_val=False
    if not any(char.islower() for char in passwd):
        print('the password should have at least one lowercase letter')
        return_val=False
    if not any(char in SpecialSym for char in passwd):
        print('the password should have at least one of the symbols $@#')
        return_val=False
    if return_val:
        print('Ok')
    return return_val

print(passwd_check.__doc__)
passwd = input('enter the password : ')
print(passwd_check(passwd))

Using `return_val` is non-pythonic. Just return False if it is not valid and True if it is. — woodpav, Oct 01 '18 at 16:15

score 1 · Answer 6 · answered Sep 22 '19 at 10:08

''' Minimum length is 5;
 - Maximum length is 10;
 - Should contain at least one number;
 - Should contain at least one special character (such as &, +, @, $, #, %, etc.);
 - Should not contain spaces.
'''

import string

def checkPassword(inputStr):
    if not len(inputStr):
        print("Empty string was entered!")
        exit(0)

    else:
        print("Input:","\"",inputStr,"\"")

    if len(inputStr) < 5 or len(inputStr) > 10:
        return False

    countLetters = 0
    countDigits = 0
    countSpec = 0
    countWS = 0

    for i in inputStr:
        if i in string.ascii_uppercase or i in string.ascii_lowercase:
             countLetters += 1
        if i in string.digits:
            countDigits += 1
        if i in string.punctuation:
            countSpec += 1
        if i in string.whitespace:
            countWS += 1

    if not countLetters:
        return False
    elif not countDigits:
        return False
    elif not countSpec:
        return False
    elif countWS:
        return False
    else:
        return True


print("Output: ",checkPassword(input()))

With Regex

s = input("INPUT: ")
print("{}\n{}".format(s, 5 <= len(s) <= 10 and any(l in "0123456789" for l in s) and any(l in "!\"#$%&'()*+,-./:;<=>?@[\]^_`{|}~" for l in s) and not " " in s))

Module import

from string import digits, punctuation

def validate_password(p):
    if not 5 <= len(p) <= 10:
        return False

    if not any(c in digits for c in p):
        return False

    if not any(c in punctuation for c in p):
        return False

    if ' ' in p:
        return False

    return True

for p in ('DJjkdklkl', 'John Doe'
, '$kldfjfd9'):
    print(p, ': ', ('invalid', 'valid')[validate_password(p)], sep='')

VishwasR Vibhu · Answer 7 · 2020-12-15T01:53:58.160

Sure with regex there are easier answers, but this one of the simplest ways

from string import punctuation as p
s = 'Vishwasrocks@23' #or user input is welcome
lis = [0, 0, 0, 0]
for i in s:
    if i.isupper():
        lis[0] = 1
    elif i.islower():
        lis[1] = 1
    elif i in p:
        lis[2] = 1
    elif i.isdigit():
        lis[3] = 1
print('Valid') if 0 not in lis and len(s) > 8 else print('Invalid')

score 1 · Answer 8 · edited Jul 01 '21 at 20:58

The simplest python validation using normal methods

password = '-'

while True:
    password = input(' enter the passwword : ')
    lenght = len(password)

    while lenght < 6:
        password = input('invalid , so type again : ')

        if len(password)>6:
            break

    while not any(ele.isnumeric() for ele in password):
        password = input('invalid , so type again : ')
    while not any(ele.isupper() for ele in password):
        password = input('invalid , so type again : ')
    while not any(ele not in "[@_!#$%^&*()<>?/|}{~:]" for ele in password):
        password = input('invalid , so type again : ')
    break

score 0 · Answer 9 · edited Jun 20 '20 at 09:12

isdigit() checks the whole string is a digit, not if the string contains a digit

Return true if all characters in the string are digits and there is at least one character, false otherwise.
isupper() checks the whole string is in uppercase, not if the string contains at least one uppercase character.

Return true if all cased characters in the string are uppercase and there is at least one cased character, false otherwise.

What you need is using the any built-in function:

any([x.isdigit() for x in password]) will return True if at least one digit is present in password
any([x.isupper() for x in password]) will return True if at least one character is considered as uppercase.

score 0 · Answer 10 · answered Dec 13 '16 at 09:51

0

Maybe you can use regex expression:

re.search(r"[A-Z]", password)

Check uppercase letters.

re.search(r"[0-9]", password)

Check digits in password.

answered Dec 13 '16 at 09:51

Marcin Świerczyna

112
4

user2557522 · Answer 11 · 2018-11-14T19:01:18.117

Python 2.7 The for loop will assign a condition number for each character. i.e. Pa$$w0rd in a list would = 1,2,4,4,2,3,2,2,5. Since sets only contains unique values, the set would = 1,2,3,4,5; therefore since all conditions are met the len of the set would = 5. if it was pa$$w the set would = 2,4 and len would = 2 therefore invalid

name = raw_input("Enter a Password: ")
list_pass=set()
special_char=['#','$','@']
for i in name:
    if(i.isupper()):
      list_pass.add('1')
  elif (i.islower()):
      list_pass.add('2')
  elif(i.isdigit()) :
      list_pass.add('3')
  elif(i in special_char):
      list_pass.add('4')
if len(name) >=6 and len(name) <=12:
    list_pass.add('5')
if len(list_pass) is 5:
    print ("Password valid")
else: print("Password invalid")

Code only answers are really discouraged. To help future readers, please explain what you are doing too! — itsmysterybox, Nov 07 '18 at 06:02

score 0 · Answer 12 · answered Apr 07 '20 at 16:01

uppercase_letter = ['A', 'B','C', 'D','E','F','G','H','I','J','K','L','M','N','O',
            'P','Q','R','S','T','U','V','W','X','Y','Z']

number = [1, 2, 3, 4, 5, 6, 7, 8, 9, 0]

import re

info ={}

while True:

    user_name = input('write your username: ')

    if len(user_name) > 15:
        print('username is too long(must be less than 16 character)')
    elif len(user_name) < 3 :
        print('username is short(must be more than 2 character)')
    else:
        print('your username is', user_name)
        break


while True:   

    password= input('write your password: ')

    if len(password) < 8 :
        print('password is short(must be more than 7 character)')

    elif len(password) > 20:
        print('password is too long(must be less than 21 character)') 

    elif re.search(str(uppercase_letter), password ) is None :
        print('Make sure your password has at least one uppercase letter in it')

    elif re.search(str(number), password) is None :
        print('Make sure your password has at least number in it')

    else:
        print('your password is', password)
        break

info['user name'] = user_name

info['password'] = password

print(info)

Can you explain how and why your code answers the questions? — Michael Heil, Apr 07 '20 at 16:25
@mike first of all , if you think my code is useful , pleas click on upwards arrow :) , and also my cose is readable , if you have problem with it , plz tell me :) — ehsanb159, Apr 08 '20 at 20:14

Dheeraj Bharambe · Answer 13 · 2022-07-12T10:51:37.660

Password Complexity conditions:

Must include at least one uppercase character
Must include at least one lowercase character
Must include at least one number
Must include at least one special character

Must have a length of at least 8 and a max of 20

 import re
 def validate():
     while True:
     password = raw_input("Enter a password: ")
     re_exp = "^(?=.*[a-z])(?=.*[A-Z])(?=.*\d)(?=.*[@$!%*#?&])[A-Za-z\d@$!#%*?&]{8,20}$"
     if re.search(re.compile(regex_exp),password):
         print("Your password seems fine")
     else:
         print("Password doees not matches with password complexity conditions")
         break

Ludwig Austermann · Answer 14 · 2018-02-28T11:22:57.300

-1

Or you can use this to check if it got at least one digit:

min(passwd).isdigit()

edited Feb 28 '18 at 11:22

answered Feb 24 '18 at 14:43

Ludwig Austermann

1
2

`max(passwd).isupper()` doesn't work at all, only in special cases – Nico Albers Feb 24 '18 at 14:50

Validation of a Password - Python

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