I would like to have an expression to validate the plates of monaco.
They are written as follows:
A123
123A
1234
I started by doing:
^[a-zA-Z0-9]{1}?[0-9]{2}?[a-zA-Z0-9]{1}$
But the case A12A which is false is possible with that.
You can use
^(?!(?:\d*[a-zA-Z]){2})[a-zA-Z\d]{4}$
See the regex demo. Details:
^ - start of string
(?!(?:\d*[a-zA-Z]){2}) - a negative lookahead that fails the match if there are two occurrences of any zero or more digits followed with two ASCII letters immediately to the right of the current location
[a-zA-Z\d]{4} - four alphanumeric chars
$ - end of string.
You can write the pattern using 3 alternatives specifying all the allowed variations for the example data:
^(?:[a-zA-Z][0-9]{3}|[0-9]{3}[a-zA-Z]|[0-9]{4})$
See a regex demo.
Note that you can omit {1} and
To not match 2 chars A-Z you can write the alternation as:
^(?:[a-zA-Z]\d{3}|\d{3}[a-zA-Z\d]|\d[a-zA-Z\d][a-zA-Z\d]\d)$
See another regex demo.
So it needs 3 connected digits and 1 letter or digit.
Then you can use this pattern :
^(?=.?[0-9]{3})[A-Za-z0-9]{4}$
The lookahead (?=.?[0-9]{3}) asserts the 3 connected digits.
Test on Regex101 here
Related
I need to build a regex that have the following:
Rules to be applied:
exactly 14 characters
only letters (latin characters) and numbers
at least 3 letters
Regex still confuses me so I am struggling to get the correct output. I want to use it with swift and swiftui in an app I am making
(?=(.*[a-zA-Z]){3,}([0-9]){0,}){14,14}$
I tried this. But I know it is not the way
I would use a positive lookahead for the length requirement:
^(?=.{14}$)(?:[A-Za-z0-9]*[A-Za-z]){3}[A-Za-z0-9]*$
This pattern says to match:
^ from the start of the input
(?=.{14}$) assert exact length of 14
(?:
[A-Za-z0-9]*[A-Za-z] zero or more alphanumeric followed by one alpha
)
[A-Za-z0-9]* any alphanumeric zero or more times
$ end of the input
You need to use
^(?=(?:[0-9]*[a-zA-Z]){3})[a-zA-Z0-9]{14}$
Details
^ - start of string
(?=(?:[0-9]*[a-zA-Z]){3}) - at least three repeations of a letter after any zero or more digits sequence required
[a-zA-Z0-9]{14} - fourteen letters/digits
$ - end of string.
See the regex demo.
The requirement is "each 2 digits must be only numbers or only text" - so valid patterns are AB-12-CD or 12-AB-CD or AB-CD-12, 12-34-AB.
The below suggested pattern working fine without hyphen but if we want to add a hyphen in between, how to do?
\b(?=[A-Z\d][A-Z])(?=[A-Z\d]\d)(?:[A-Z]{2}|\d{2})+\b
Repeat 1 or more times matching either 2 uppercase chars or 2 digits. Note that there are no hyphens present in the example data.
\b(?:[A-Z]{2}|\d{2})+\b
Regex demo
If there must be a digit and an uppercase character present, you could also use a positive lookahead:
\b(?=[A-Z\d]*[A-Z])(?=[A-Z\d]*\d)(?:[A-Z]{2}|\d{2})+\b
Regex demo
For strings like Cisco 3750 i7706-cm021 10.123.12.34 -> 10.123.34.12 I would like to get result Cisco 3750 i7706-cm021 10.123.12.34 -> using expression ^.*(?![\d\.]{12}$). But instead a whole string is matched. What is the correct expression would be?
You may use a regex like
^.*?(?=\b(?:\d{1,3}\.){3}\d{1,3}$)
See the regex demo and the Regulex graph:
Details
^ - start of string
.*? - any 0+ chars other than line break chars, as few as possible
(?=\b(?:\d{1,3}\.){3}\d{1,3}$) - a positive lookahead that requires (immediately to the right of the current location):
\b - word boundary
(?:\d{1,3}\.){3} - three repetitions of 1 to 3 digits and a dot
\d{1,3} - one to three digits
$ - end of string.
To get more precise IP regex, see How to Find or Validate an IP Address:
^.*?(?=\b(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$)
See the regex demo
I'm having issues with the validation of the chilean RUT/RUN with a regex expression in PCRE. I have the next regular expression but sadly can't make it work:
\b[0-9|.]{1,10}\-[K|k|0-9]
I need help to see what is wrong with the code. The application I need to use only uses PCRE.
Thank you.
You may use
^(\d{1,3}(?:\.\d{1,3}){2}-[\dkK])$
to match and capture (that is not usually necessary, but your app requires a capturing group to extract its contents) a whole string that matches the pattern. See the regex demo.
To match shorter strings that match this pattern inside a larger string, you may remove ^ and $ (see demo) or use \b word boundaries instead (see this demo).
Details:
^ - start of string
\d{1,3} - 1 to 3 digits
(?:\.\d{1,3}){2} - 2 sequences of a literal . and 1 to 3 digits
- - a hyphen
[\dkK] - a digit, k or K.
$ - end of string.
As they sometimes omit the dots, I used this one:
^(\d{1,2}(?:[\.]?\d{3}){2}-[\dkK])$
Details:
^ - start of string
\d{1,2} - 1 or 2 digits
(?:[.]?\d{3}){2} - 2 sequences of an optional '.' and 3 digits
- a hyphen
[\dkK] - a digit, k or K
$ - end of string
1234567-k OK
12345678-k OK
1.234.567-k OK
12.345.678-k OK
known issue:
12.345678-k and 12345.678-k still OK and I do not like this :(
You need to change to ^(\d{1,3}(?:\.\d{3}){2}-[\dkK])$ to capture only 2 sequence of 3 digits after the first sequence of 1-3 digits.
please consider being more specific in the REGEX build, since it matched wrong numbers, such as 17.87.335-2. Also the included one did't match formats without the dots or the hyphens.
Please consider using the following format: \b(\d{1,3}(?:(.?)\d{3}){2}(-?)[\dkK])\b
Modified prior version to try the other formats: https://regex101.com/r/2Us0j6/9
I am trying to write a regular expression that will match a two digit number where the two digits are not same.
I have used the following expression:
^([0-9])(?!\1)$
However, both the strings "11" and "12" are not matching. I thought "12" would match. Can anyone please tell me where I am going wrong?
You need to allow matching 2 digits. Your regex ^([0-9])(?!\1)$ only allows 1 digit string. Note that a lookahead does not consume characters, it only checks for presence or absence of something after the current position.
Use
^(\d)(?!\1)\d$
^^
See demo
Explanation of the pattern:
^ - start of string
(\d) - match and capture into Group #1 a digit
(?!\1) - make sure the next character is not the same digit as in Group 1
\d - one digit
$ - end of string.