正则表达式不超过2个连续数字不超过2个重复字符？

Question

I am looking to create a regex with conditions:

• Minimum length 6
• At least one number and one letter must be used
• No more than 2 consecutive numbers (like 123)
• No more than 2 repeated characters

What I am able to achieve

/^(?!.*([A-Za-z0-9!@#$&()\\-`.+,/?"])\1{2})(?=.*[a-z])(?=.*\d)[A-Za-z0-9!@#$&()\\-`.+,/?"]+$/

This validates that the string has at least one number and one letter. Instead of consecutive numbers 123, it checks 111. and i am not able to add 4th condition in this.

Any further help will be appreciated. Thanks in advance.

Answer 1

Try this Regex:

^(?=[\D]*\d)(?=[^a-zA-Z]*[a-zA-Z])(?=.{6,})(?!.*(\d)\1{2})(?!.*([a-zA-Z])(?:.*?\2){2,}).*$

Demo

Explanation:

• ^ - start of the string
• (?=[\\D]*\\d) - positive lookahead - checks for the presence of a digit
• (?=[^a-zA-Z]*[a-zA-Z]) - positive lookahead - checks for the presence of a letter
• (?=.{6,}) - positive lookahead - checks for the presence of atleast 6 literals
• (?!.*(\\d)\\1{2}) - Negative lookahead - Checks for the ABSENCE of 3 consecutive digits. It will allow 2 consecutive digits though. If you do not want even 2 consecutive digits, then remove {2} from this part
• (?!.*([a-zA-Z])(?:.*?\\2){2,}) - Negative lookahead - validates that no letter should be present more than 2 times in the string
• .* - capture the string
• $ - end of the string

OUTPUT:

jj112233         -Matches as it has atleast one letter, digit. Not more than 2 consecutive digits/letter. Has atleast 6 characters
jkhsfsndbf8uwwe  -matches 
a1234            -does not match as length<6 
nsds312          -matches
111aaa222        -does not match as it has more than 2 consecutive digits and also more than 2 repeated letters 
aa11bbsd         -match
hgshsadh12       -does not match as it has more than 2 `h`
hh8uqweuu        -does not match as it has more than 2 `u`