Regex with 3 characters long and at least one letter - regex

I wondering if it is possible to have this test in one regex
Length at least 3 and at least one letter
I test regex like this
([a-zA-Z]{1,}).(\w{3,})
but not working
sample :
Z56 => OK
1567 => KO
EE => KO
thx you
78 I => OK

What you are looking for as I understand is this one:
^(?:([a-zA-Z]{1})(\w{0,2})|((?:\s*\w){0,3}))$
I added ^ and $ to specify that the string must start and end, and The second part {0,2} to set the length between 0 and 2, you can change the first part {1} with ? to accept empty strings, and the alternative | to capture the last example 78 I

If you want to capture the characters then:
^(?=.*[A-Za-z])\w{3,}$
See Regex Demo
^ Matches the start of the string.
(?=.*[A-Za-z]) Is a positive lookahead assertion requiring that the input contains a letter.
\w{3,} Matches 3 or more word characters (so the input must be length 3 or longer).
$ Matches the end of the string.
Use the following regex if the input can be 3 or more characters of any type as long as there is at least one letter (there is a discrepancy between the the question title, which just states 3 characters and the regex you attempted), so it is not entirely clear which one is intended:
^(?=.*[A-Za-z]).{3,}$

(?=.*[A-Za-z]).{3,}
Should work.

Related

RegEx to check 24 hours time format fails

I have the following RegEx that is supposed to do 24 hours time format validation, which I'm trying out in https://rubular.com
/^[0-23]{2}:[0-59]{2}:[0-59]{2}$/
But the following times fails to match even if they look correct
02:06:00
04:05:00
Why this is so?
In character classes, you're supposed to denote the range of characters allowed (in contrast to the numbers you want to match in your example). For minutes and seconds, this is relatively straight-forward - the following expression
[0-5][0-9]
...will match any numerical string from "00" to "59".
But for the hours, you need to two separate expressions:
[01][0-9]|2[0-3]
...one to match "00" to "19" and one to match "20" to "23". Due to the alternative used (| character), these need to be grouped, which adds another bit of syntax (?:...). Finally we're just adding the anchors ^ and $ for beginning and end of string, which you already had where they belong.
^(?:[01][0-9]|2[0-3]):[0-5][0-9]:[0-5][0-9]$
You can check this solution out at regex101, if you like.
Your problem is that you understand characters ranges wrong: 0-23 doesn't mean "match any number from 0 to 23", it means: 0-2- match one digit: 0,1 or 2, then match 3.
Try this pattern: (?:[01][0-9]|2[0-3])(?::[0-5][0-9]){2}
Explanation:
(?:...) - non-capturing group
[01][0-9]|2[0-3] - alternation: match whether 0 or one followed by any digits fro 0 to 9 OR 2 followed by 0, 1, 2 or 3 (number from 00-23)
(?::[0-5][0-9]){2} - match : and [0-5][0-9] (basically number from 00-59) twice
Demo
use this (([0-1]\d|[2][0-3])):(([0-5][0-9])):(([0-5][0-9]))
Online demo

Regex ignore first x characters and then match pattern

String = '11111111111110000000000000000000110000000000000011111111111111111111111111111111110011111111111110000011110000011111111111110000000000011111111111111111010001111111111111111111110011111111111111111111111111110111112111121111111111111111111000011000001011111111111101022111101111001111111111110000001000000111111111111111000000000000011111111111111100011111111001011111111100000000000000000000000000000000100111001000000000000000000011000000000000001111111000000000000000000000000000000000001111100000000000000000000011000000000000000000000010000000000333333333'
I want a pattern to take out 10 characters after the first 100 so i want to have 100 - 110 then I want to compare that one and see if that string with a length of 10 have 4 zeros in a row.
How can I do this with only Regex? I have been using substring before.
You could use this:
^.{100}(?=.{0,6}0000)(.{10})
Explanation:
^: matches the start of the string to avoid that the pattern is used anywhere in the input
.{100}: match 100 characters
(?= ): look ahead. This does not capture, but just verifies something that is still ahead.
.{0,6}: 0 to 6 characters
0000: literally 4 zeroes
(.{10}): 10 characters, this time they are captured and can be referenced back with \1 or $1 depending on the flavour of regex.
The above answer is perfect. But that matches all the characters including first 100.
In case of ignoring first 100, we can use
(?<=.{100})
To check the required pattern in last 10 characters after first 100 only, we can use
(?<=.{100})(?=.{0,6}0000)(.{10})
You can test it here
Update : I checked the link today. It's taking somewhere else.

Reg Exp: match specific number of characters or digits

My RegExp is very rusty! I have two questions, related to the following RegExp
Question Part 1
I'm trying to get the following RegExp to work
^.*\d{1}\.{1}\d{1}[A-Z]{5}.*$
What I'm trying to pass is x1.1SMITHx or x1.1.JONESx
Where x can be anything of any length but the SMITH or JONES part of the input string is checked for 5 upper case characters only
So:
some preamble 1.1SMITH some more characters 123
xyz1.1JONES some more characters 123
both pass
But
another bit of string1.1SMITHABC some more characters 123
xyz1.1ME some more characters 123
Should not pass because SMITH now contains 3 additional characters, ABC, and ME is only 2 characters.
I only pass if after 1.1 there are 5 characters only
Question Part 2
How do I match on specific number of digits ?
Not bothered what they are, it's the number of them that I can't get working
if I use ^\d{1}$ I'd have thought it'll only pass if one digit is present
It will pass 5 but it also passes 67
It should fail 67 as it's two digits in length.
The RegExp should pass only if 1 digit is present.
For the first one, check out this regex:
^.*\d\.\d[A-Z]{5}[^A-Z]*$
Before solving the problem, I made it easier to read by removing all of the {1}. This is an unnecessary qualifier since regex will default to looking for one character (/abc/ matches abc not aaabbbccc).
To fix the issue, we just need to replace your final .*. This says match 0+ characters of anything. If we make this "dot-match-all" more specific (i.e. [^A-Z]), you won't match SMITHABC.
I came up with a number of solution but I like these most. If your RegEx engine supports negative look-ahead and negative look-behind, you can use this:
Part 1: (?<![A-Z])[A-Z]{5}(?![A-Z])
Part 2: (?<!\d)\d(?!\d)
Both have a pattern of (?<!expr)expr(?!expr).
(?<!...) is a negative look-behind, meaning the match isn't preceded by the expression in the bracket.
(?!...) is a negative look-ahead, meaning the match isn't followed by the expression in the bracket.
So: for the first pattern, it means "find 5 uppercase characters that are neither preceded nor followed by another uppercase character". In other words, match exactly 5 uppercase characters.
The second pattern works the same way: find a digit that is not preceded or followed by another digit.
You can try it on Regex 101.

Regular Expression for testing length of string part

Hi I need a regular expression which is accepting the following strings:
[A-Z]-[A-Z]{3-5}[0-9]{2-4}
for example X-ABC123 or Y-AB1234
The problem now is that the total length of the string on the right side of the hyphen must always be 5 chars in length. Is there a chance to check that with regular expressions only?
Just add this after the hyphen :
/(?=[A-Z\d]{5}$)/
Resulting in :
/^[A-Z]-(?=[A-Z\d]{5}$)[A-Z]{3,5}[0-9]{2,4}/
This assumes that your input strings are the strings you posted.
X-ABC123 -> fails
Y-AB1234 -> fails
A-ABD12 -> matches
A-ABV111 -> fails
If the string is part of another string you can replace the $ anchor with \s|$ for example.
First the problems in your regex
The quantifier is {3,5} and not {3-5} (this would match literally "{3-5}")
You want 3 to 5 letters and 2 to 4 digits and in total 5 letters and digits ==> the only valid combination is then 3 letters followed by 2 digits.
In general you can use a positive lookahead for this
^[A-Z]-(?=.{5}$)[A-Z]{3,5}[0-9]{2,4}$
See it here on Regexr
The (?=.{5}$) part is just looking, if there are from its position to the end ($) 5 characters.
But as said before, if the 3-5 and 2-4 and overall 5 is valid you can just do
^[A-Z]-[A-Z]{3}[0-9]{2}$
I think it's definitely possible, from a language theory point of view. Just group it and add the constraint :
I just need to know which language is specifying the regex but something like this :
[A-Z]-(^[A-Z][A-Z0-9]4)
I had the feeling you wanted the right part to start with one char for sure, then either chars or numbers

Regex allow a string to only contain numbers 0 - 9 and limit length to 45

I am trying to create a regex to have a string only contain 0-9 as the characters and it must be at least 1 char in length and no more than 45. so example would be 00303039 would be a match, and 039330a29 would not.
So far this is what I have but I am not sure that it is correct
[0-9]{1,45}
I have also tried
^[0-9]{45}*$
but that does not seem to work either. I am not very familiar with regex so any help would be great. Thanks!
You are almost there, all you need is start anchor (^) and end anchor ($):
^[0-9]{1,45}$
\d is short for the character class [0-9]. You can use that as:
^\d{1,45}$
The anchors force the pattern to match entire input, not just a part of it.
Your regex [0-9]{1,45} looks for 1 to 45 digits, so string like foo1 also get matched as it contains 1.
^[0-9]{1,45} looks for 1 to 45 digits but these digits must be at the beginning of the input. It matches 123 but also 123foo
[0-9]{1,45}$ looks for 1 to 45 digits but these digits must be at the end of the input. It matches 123 but also foo123
^[0-9]{1,45}$ looks for 1 to 45 digits but these digits must be both at the start and at the end of the input, effectively it should be entire input.
The first matches any number of digits within your string (allows other characters too, i.e.: "039330a29"). The second allows only 45 digits (and not less). So just take the better from both:
^\d{1,45}$
where \d is the same like [0-9].
Use this regular expression if you don't want to start with zero:
^[1-9]([0-9]{1,45}$)
If you don't mind starting with zero, use:
^[0-9]{1,45}$
codaddict has provided the right answer. As for what you've tried, I'll explain why they don't make the cut:
[0-9]{1,45} is almost there, however it matches a 1-to-45-digit string even if it occurs within another longer string containing other characters. Hence you need ^ and $ to restrict it to an exact match.
^[0-9]{45}*$ matches an exactly-45-digit string, repeated 0 or any number of times (*). That means the length of the string can only be 0 or a multiple of 45 (90, 135, 180...).
A combination of both attempts is probably what you need:
^[0-9]{1,45}$
^[0-9]{1,45}$ is correct.
Rails doesnt like the using of ^ and $ for some security reasons , probably its better to use \A and \z to set the beginning and the end of the string
For this case word boundary (\b) can also be used instead of start anchor (^) and end anchor ($):
\b\d{1,45}\b
\b is a position between \w and \W (non-word char), or at the beginning or end of a string.