I'm trying to make a number input field using the pattern attribute since the regular type number didn't support the validations I needed.
Essentially, I want to allow any numbers that make sense, including $, + or - at the start and a % at the end. Also, users should be able to separate their numbers with commas to avoid mistakes on long numbers, but this is not necessary and they should still be able to submit a long number without any type of separation. The field should also allow for decimals.
<input required pattern="[+-]?\$?\d+(,\d{3})*(\.\d+)?%?" type="text" />
I need to allow for the following examples:
Pass:
2000
-20%
2,000
$2,000.00
999,999,999,999,999,999,999.99
Fail:
123e9
Anything that has letters on it
This is the regex that I have so far, but it doesn't seem to work, even for the most basic numbers. I've been using scriptular to test my regex, but that doesn't seem to reflect the results of the actual HTML validation.
Regex: [+-]?\$?\d+(,\d{3})*(\.\d+)?%?
EDIT: For any Ruby on Rails devs, I realized one of my mistakes is that you must escape any backslashes in your regex when you are generating your text_field. So for example, the regex in the answer should look like (?:\\+|\\-|\\$)?\\d{1,}(?:\\,?\\d{3})*(?:\\.\\d+)?%?
Try with following regex.
Regex: (?:\+|\-|\$)?\d{1,}(?:\,?\d{3})*(?:\.\d+)?%?
Explanation:
(?:\+|\-|\$)? matches either + - or $ in-front of a number which is optional as ? quantifier is used.
\d{1,} matches integer part even if it doesn't have ,.
(?:\,?\d{3})* matches multiple occurrences of comma separated digits if present.
(?:\.\d+)? matches optional decimal part.
%? matches optional % character in the end.
?: stands for non-capturing groups. It will match but won't store it for back-referencing.
Regex101 Demo
Related
I have an HTML5 input element with a pattern attribute. I'm having some trouble with an optional group.
The (relative) URL must start with a forward slash (I have this working).
The total (relative) URL may contain a total of up to 255 characters.
All characters from 2-255 must be (lowercase) alpha-numeric or a forward slash.
Separately the forward slash regex works and the 2-255 part works for alpha-numeric and forward slashes. However I'm having trouble allowing both groups with the second group being optional.
What I have confirmed to work:
pattern="^\/"
pattern="[a-z0-9\/]"
However I can't determine how to allow the second group as an option (I've tried adding the ? after the ending square bracket in example without luck).
I also am not sure how to combine the length ({255,}) bit to the total pattern expression.
How do I combine all three aspects of the regular expression?
Note: tags seem to be broken at the moment of posting this.
You can use
pattern="/[a-z0-9/]{0,254}"
You do not need ^ nor $ in the pattern regex, by the way, it must match the whole string anyway, it will be parsed as ^(?:/[a-z0-9/]{0,254})$ pattern. That is, it will match a string that starts with / and then contains 0 to 254 lowercase ASCII letters, digits or slashes till the string end.
Note that / should only be escaped in regex literals where / is used as a delimiter char. pattern regexps are defined with literal strings.
I'm trying to combine two regexes. One will ensure that input contains 14 digits: ^\\d{14}$ and I need another regex to check if all the input is not of the same digit.
Please suggest how I proceed with this. I want my regex to check for that the input is 14 digits and those digits are not all same numbers [0-9].
Is there a way I add the test for finding not all digits are the same with my regex that checks for if the input is exactly 14 digits? I would need one regex expression which combines them both. Thank you!
You can use negative lookahead with a back reference to the first digit:
(?!(\d)\1{13})\d{14}$
NB: This is pure regex syntax. I did not escape backslashes for use in a programming language.
There is no regex operation for "match here for all-of-these except a back-reference". You have a two-step test here, not a single one.
I have a password field and I need to check if it has at least 8 characters and if it has the following characters:
! # # $ % ^ & *
I tried to do it using a pattern, and it's not working as expected:
<div class="col-sm-6 form-group">
<input type="password" class="form-control" id="Clave" name="txtClave"
pattern='/[!##$%^&*(),.?":{}|<>]/g.{8,}'
title="Debe contener uno de los siguientes caracteres: ! # # $ % ^ & *, y al menos 8 o más caracteres" required>
</div>
Try Regex: ^(?=.*[!##$%^&*(),.?":{}|<>]).{8,}$
Demo
The best mechanism for combining multiple tests in a single regex is a lookahead. An ordinary regex moves through a string looking for a match, which means that when it finds a match it is no longer at the beginning of the string. A lookahead looks for a match without actually moving (hence the name "lookahead"). The basic format is (?=<regex>) and you can combine as many as you like into a single pattern.
In this case, you have two conditions, so you'll want to combine two lookaheads. We've already seen the first -- .{8,} -- but in a lookahead you want a little more than that: you need to ensure that the regex matches the entire string. So start your pattern with \A, the anchor matching the beginning of the string, and end the lookahead with \z, the anchor matching the end of the string. Put it together and the first part of your pattern is \A(?=.{8,}\z). (This precaution is unnecessary in your specific case, because you'll accept passwords with more than eight characters, but it's still good practice.)
The second condition, matching any of eight specific characters, starts with the class [!##$%^&*]. But in a lookahead that starts at the beginning of the string and never moves, that class would match only the first character. You need a regex that matches anywhere in the string. An easy way to do this is .*[!##$%^&*], which matches zero or more characters followed by one of your special characters. In a lookahead, that would be (?=.*[!##$%^&*]). "Easy" is not always best, however: the .* construct is comparatively inefficient, because it always checks the entire string and then has to backtrack to the beginning before continuing, which can be computationally expensive.
A much more efficient way to do something like this is [^!##$%^&*]*[!##$%^&*]. This matches zero or more characters that are not in your special set, followed by exactly one character that is. (A caret (^) as the first character in a bracketed class means to negate the class; a caret anywhere else in the class is just a literal caret as a member of the class.) It's more efficient because it checks only the characters before its position in the string, and can stop immediately once it finds a match. Putting that in a lookahead gives us (?=[^!##$%^&*]*[!##$%^&*]).
Now you can simply combine the two lookaheads into your "pattern", like so:
pattern='\A(?=.{8,}\z)(?=[^!##$%^&*]*[!##$%^&*])'
That should match any password with eight or more characters, at least one of which is one of your eight special characters: ! # # $ % ^ & *
Is there a way to associate two regex ?
I have this one which prevents user to use this email (test#test.com)
pattern="^((?!test#test.com).)*$"
I also have one which validates email syntax
pattern="[a-z0-9._%+-]{3,}#[a-z]{3,}([.]{1}[a-z]{2,}|[.]{1}[a-z]{2,}[.]{1}[a-z]{2,})"
How to merge those two regex in order to prevent user to user test#test.com and to validate the email syntax ?
I tried to use an OR operator (single pipe) but I am missing something, it doesn't work ...
Thanks !
It seems you may use
pattern="(?!test#test\.com$)[a-z0-9._%+-]{3,}#[a-z]{3,}\.[a-z]{2,}(?:\.[a-z]{2,})?"
Note that the HTML5 patterns are automatically anchored as they are wrapped with ^(?: and )$ at the start/end, so no need adding ^ and $ at the start/end of the pattern.
The (?!test#test\.com$) negative lookahead will fail the match if the input string is equal to the test#test.com string (unlike your first regex that only fails the input that contains the email).
The rest is your second pattern, I only removed {1} that are implicit and contracted an alternation group to a \.[a-z]{2,}(?:\.[a-z]{2,})? where (?:\.[a-z]{2,})? is an optional non-capturing group matching 1 or 0 sequences of . and 2 or more lowercase ASCII letters.
Add A-Z to the character classes to also support uppercase ASCII letters.
I am trying to extract an email address from user input text in Watson Conversation. First thing first, I need to trigger a particular node using an if condition like this:
input.text.contains('\^(([^<>()[].,;:s#\"]+(.[^<>()[].,;:s#\"]+)*)|(\".+\"))#(([[0-9]{1,3}.[0-9]{1,3}.[0-9]{1,3}.[0-9]{1,3}])|(([a-zA-Z-0-9]+.)+[a-zA-Z]{2,}))$\')
But it doesn't work, I tried a lot of regexes that I found on the internet but none of them work. Does anyone know how to write a proper regex?
I suggest using a much simpler, approximate, regex to match emails that you need to use with String.matches(string regexp) method that accepts a regex:
input.text.matches('^\\S+#\\S+\\.\\S+$')
Do not forget to double escape backslashes so as to define literal backslashes in the pattern.
Pattern details:
^ - start of string
\\S+ - one or more non-whitespace chars
# - a # symbol
\\S+ - one or more non-whitespace chars
\\. - a literal dot
\\S+ - one or more non-whitespace chars
$ - end of string.