Regular expression to match an UID

Question

I'm trying to validate an UID which has the following rules

1. It must contain at least 2 uppercase English alphabet characters.
2. It must contain at least 3 digits (0-9).
3. It should only contain alphanumeric characters.
4. No character should repeat.
5. There must be exactly 10 characters in a valid UID.

I have tried it doing by regular expression but I'm unable to create a pattern which can satisfy all the rules.

So I did it without the regular expression.

#import re
#pattern = r'^[A-Z0-9]{10}$'

testCases = int(input())

for _ in range(testCases):
    uid = input()
    if len(uid) == 10 and len(uid) == len(set(uid)):
       countChr = countNum = 0
       for i in uid:
           if i.isdigit():
               countNum += 1
           elif i.isalpha():
               countChr +=1
       if countChr >= 2 and countNum >= 3:
           print("Valid")
       else:
           print("Invalid")
   else:
       print("Invalid")

The above program worked perfectly but I want to validate the UID with regular expression, so is there any pattern which can satisfy all the given rules?

Answer 1

Try this regex:

^(?=(?:.*[A-Z]){2})(?=(?:.*[0-9]){3})(?:([a-zA-Z0-9])(?!.*\1)){10}$

^                           beginning of the text

    (?=                     positive lookahead
        (?:                 non-capturing group
            .*[A-Z]         anything followed by an uppercased letter
        ){2}                match 2 of them
    )                       end of the lookahead

    (?=                     positive lookahead
        (?:                 non-capturing group
            .*[0-9]         anything followed by a digit
        ){3}                match 3 of them
    )                       end of the lookahead

    (?:                     non-capturing group
        ([a-zA-Z0-9])       any alphanumeric character and put it in group 1
        (?!.*\1)            negative lookahead, make sure there's no repeated character ahead
    ){10}                   match 10 of them
    
$                           end of the text

Check the test cases

Using python

import re

pattern = r'^(?=(?:.*[A-Z]){2})(?=(?:.*[0-9]){3})(?:([a-zA-Z0-9])(?!.*\1)){10}$'
testCases = int(input())

for _ in range(testCases):
    uid = input()
    if re.match(pattern, uid):
        print("Valid")
    else:
        print("Invalid")