Identify if there are two of the same character adjacent to eachother

Question

I've been asked to create a program that identifies if a password is valid or not. The one part I am struggling with is identifying whether there are two of the same character adjacent to each other. Help would be appreciated and here is the program so far:

import re

pswrd = input("Enter Desired Password:")

if len(pswrd) < 6:
    print("Password must have more than 6 characters.")
if len(pswrd) > 15:
    print("Password must have no more than 15 characters.")
if re.search("[$#@]",pswrd):
    print("Password must have no special characters.")
if not re.search("[0-9]",pswrd):
    print("Password must contain a number.")
if not re.search("[a-z]",pswrd):
    print("Password must contain a lower case letter.")
if not re.search("[A-Z]",pswrd):
    print("Password must contain an upper case letter.")

Answer 1

The regex to check for adjacent characters is

(.)\1

The period (.) matches any character. The brackets create a capturing group around that character, which is then referenced by \1.

So, the condition would be:

if re.search(r"(.)\1", pswrd)

Note the r character before the regular expression. This makes it a raw string. Regular expressions should always be made raw strings. This ensures that certain special characters in the regex (like \b) are not interpreted before being passed to the re module.

You can test the regular expression here: http://regexr.com/3h0g0