I am trying to validate a second level domain (everything before the .com and after the https://) in Ruby so that I can pass it into my namecheap api requests. Here is what I have so far, but I am not familiar with regex
validates_format_of :sld, with: [a-zA-Z0-9-]
no spaces allowed
no special characters allowed
however, dashes are allowed
cannot start with a dash
cannot end with a dash
I know that uppercase characters do not work in domain names, but I don't want to make users enter their text again. I will downcase the user input and show a flash message on the next page.
How about
validates_format_of :sld, with: /\A[a-z\d][a-z\d-]*[a-z\d]\z/i
Explanation:
\A - match beginning of string
[a-z\d] - match any letter from a-z or number from 0-9 once
[a-z\d-] - match any letter from a-z, number from 0-9, or dash zero or more times
[a-z\d] - match any letter from a-z or number from 0-9 once
\z - match end of string
i flag - make matches case-insensitive
Note: this will only work for strings of length 2 or more. If you need to support single-character inputs,
I would just write a method that checks the string length and if it's a single character, ensure it's not a dash. If it's more than 2 characters, validate it with this regex.
This will probably work:
^[0-9A-Za-z](|[-0-9A-Za-z]{0,61}[0-9A-Za-z])$
Your string needs to start with a alphanumeric ([0-9A-Za-z])
Then, there are two choices ((|[-0-9A-Za-z]{0,61}[0-9A-Za-z])):
End of string
Between 0 and 61 alphanumeric or dash chars followed by an alphanumeric char. (For a maximum of 63 characters)
^ and $ are anchors
validates :sld, format: { with: /^(?!-)[-\w\d]{,63}(?<!-)$/i }
You can try out your regex at http://rubular.com/
^(?!-) - negative lookahead: cannot start with dash
[-\w\d] - match words \w, digits \d, or dash -
{,63} - match must be between 1 and 63 characters
(?<!-)$ - negative lookbehind: cannot end with dash
/i - case insensitive
Related
I have following individual regular expressions I want to combine them using AND condition , I am using them for validating password
.[A-Z]+. - validate uppercase (one letter uppercase min)
.[0-9]+. - validate number ( one number atleast )
.[a-z]+. - validate lowercase ( one lower case minimum )
.{8,} - validate min character 8
.[^A-Za-z0-9]. - validate special character (atleast one special character )
(.)\1 - validate consecutive characters (no consecutive characters )
Right now I am validating every character separately , but i want to do it in one function only
I tried following way of combining
/^((.)\1)(.[A-Z]+.)(.[a-z]+.)(.[0-9]+.)(.[^A-Za-z0-9].).*$/
Above doesn't have all the expressions but I am trying to show how I have done.
One option is to use a set of positive lookaheads using negated character classes:
^(?=[^A-Z]*[A-Z])(?=[^a-z]*[a-z])(?=[^0-9]*[0-9])(?!.*(.)\1)(?=[a-zA-Z0-9]*[^A-Za-z0-9\s])\S{8,}$
That will match:
^ Start of string
(?=[^A-Z]*[A-Z]) Assert uppercase
(?=[^a-z]*[a-z]) Assert lowercase
(?=[^0-9]*[0-9]) Assert digit
(?!.*(.)\1) Assert no consecutive char
(?=[a-zA-Z0-9]*[^A-Za-z0-9\s]) Assert char other than listed including a whitespace char (assuming that would not be allowed)
\S{8,} Match 8+ times a non whitespace char
$ End of string
Regex demo
Note that \S for the allowed chars is a broad match, you could specify what you would allow to match using a character class.
please i want to validate the inputs from a user, the format for the inputs would be: 3 uppercase characters, 3 integer numbers, an optional space, a -, an optional space, either a 'LAB or ((EN or ENLH) with 1 interger number ranging from a [1-9]).
The regex i wrote is
/\D{3}\d{3}\s?-\s?(LAB|(EN(LH)?\d{1}))/
am finding it difficult to stop inputs after the LAB so that when EEE333 - LAB1 is inputed it becomes invalid.
If you are asking how to prevent LAB1 at the end, use an end of line anchor $ in your regex test:
/\D{3}\d{3}\s?-\s?(LAB|(EN(LH)?\d{1}))$/
If you are trying to require exactly one digit at the end of the acceptable strings, move the single digit match outside of the optional groups:
/\D{3}\d{3}\s?-\s?(LAB|(EN(LH)?))\d{1}$/
I have wrote for you the following regular expression:
[A-Z]{3}[0-9]{3}\s?-\s?(?:LAB|(?:EN|LH))[1-9]{1}
The regex works a follows:
[A-Z]{3}
MATCH EXACTLY THREE UPPERCASE CHARACTERS RANGING FROM A TO Z
[0-9]{3}
MATCH EXACTLY THREE NUMBERS RANGING FROM 0 TO 9
\s?\-\s?
MATCH a space (optional) or a '-' (required) or a space (optional)
(?:LAB|(?:EN|LH))
MATCH 'LAB' OR ('EN' OR 'LH')?: omits capturing LAB OR EN OR LH
[1-9]{1}
MATCH EXACTLY ONE NUMBERS RANGING FROM 1 TO 9
You could place your regex between word boundaries \b.
You start your regex with \D which is any character that is not a digit. That would for example also match $%^. You could use [A-Z].
You use \d{1} which is a shorhand for [0-9], but you want to match a digit between 1 and 9 [1-9]. You could also omit the {1}.
Maybe this updated will work for you?
\b[A-Z]{3}\d{3} ?- ?(?:LAB|(?:EN(?:LH)?[1-9]))\b
Explanation
A word boundary \b
Match 3 uppercase characters [A-Z]{3}
Match 3 digits \d{3}
Match an optional whitespace, a hyphen and another optional whitespace ?- ?
A non capturing group which for example matches LAB or EN EN1 or ENLH or ENLH9 (?:EN(?:LH)?[1-9]))
A word boundary \b
I have two regular expressions: ^(\\p{L}|[0-9]|_)+$ and #[^[:punct:][:space:]]+ (the first is used in Java, the second on iOS). I want to combine these into one expression, to match either one or the other in iOS.
The first one is for a username so I also need to add a # character to the start of that one. What would that look like?
The ^(\\p{L}|[0-9]|_)+$ pattern in Java matches the same way as in ICU library used in iOS (they are very similar): a whole string consisting of 1 or more Unicode letters, ASCII digits or _. It is poorly written as the alternation group is quantified and that is much less efficient than a character class based solution, ^[\\p{L}0-9_]+$.
The #[^[:punct:][:space:]]+ pattern matches a # followed with 1 or more chars other than punctuation/symbols and whitespace chars (that is, 1 or more letters or digits, or alphanumeric chars).
What you seek can be writtern as
#[\\p{L}0-9_]+|[^[:punct:][:space:]]+
or
#[\\p{L}0-9_]+|#[[:alnum:]]+
or if you want to limit to ASCII digits and not match Unicode digits:
#[\\p{L}0-9_]+|#[\\p{L}0-9]+
It matches
# - a # symbol
[\\p{L}0-9_]+ - 1 or more Unicode letters, ASCII diigts, _
| - or
# - a # char
[[:alnum:]]+ - 1 or more letters or digits.
[^[:punct:][:space:]]+ - any 1+ chars other than punctuation/symbols and whitespace.
Basically, all these expressions match strings like this.
If you want to match #SomeThing_123 in full, just use [##]\\w+, a # or # and then 1 or more letters, digits or _, or to only allow ASCII digits, [##][\\p{L}0-9_]+.
A word boundary may be required at the end of the pattern, [##][\\p{L}0-9_]+\\b.
This is the regular expression which i have, i need to make sure that string does not start or end with underscore , underscore may appear in between.
/^[a-zA-Z0-9_.-]+$/
I have tried
(?!_)
But doesn't seem to work
Allowed strings:
abcd
abcd_123
Not allowed strings:
abcd_
_abcd_123
Not too hard!
/^[^_].*[^_]$/
"Any character except an underscore at the start of the line (^[^_]), then any characters (.*), then any character except an underscore before the end of the line ([^_]$)."
This does require at least two characters to validate the string. If you want to allow one character lines:
/^[^_](.*[^_]|)$/
"Anything except an underscore to start the line, and then either some characters plus a non-underscore character before end-of-line, or just an immediate end-of-line.
You could approach this in the inverse way,
Check all those that do match starting and ending underscores like this:
/^_|_$/
^_ #starts with underscore
| #OR
_$ #ends with underscore
And then eliminate those that match. The above regexp is much more easier to read.
Check : http://www.rubular.com/r/H3Axvol13b
Or you can try the longer regex:
/^[a-zA-Z0-9.-][a-zA-Z0-9_.-]*[a-zA-Z0-9.-]$|^[a-zA-Z0-9.-]+$|^[a-zA-Z0-9.-][a-zA-Z0-9.-]$/
^[a-zA-Z0-9.-] #starts with a-z, or A-Z, or 0-9, or . -
[a-zA-Z0-9_.-]* #anything that can occur and the underscore
[a-zA-Z0-9.-]$ #ends with a-z, or A-Z, or 0-9, or . -
| #OR
^[a-zA-Z0-9.-]$ #for one-letter words
| #OR
^[a-zA-Z0-9.-][a-zA-Z0-9.-]$ #for two letter words
Check: http://www.rubular.com/r/FdtCqW6haG
/^[a-zA-Z0-9.-][a-zA-Z0-9_.-]+[a-zA-Z0-9.-]$/
Try this
Description:
In the first section, [a-zA-Z0-9.-], regex only allows lower and upper case alphabets, digits, dot and hyphen.
In the next section, [a-zA-Z0-9_.-]+, regex looks for a single or more than one characters that are lower or upper case alphabets, digits dot, hyphen or an underscore.
The last part, [a-zA-Z0-9.-], is the same as the first part that restricts the input to end with an underscore.
Try this:
Recently had the same concern and this is how I did it.
// '"^[a-zA-Z0-9_.-]*$"' → Alphanumeric and 「.」「_」「-」
// "^[^_].*[^_]$" → Reject start and end of string if contains 「_」
// (?=) REGEX AND operator
SLUG_REGEX = '"(?=^[a-zA-Z0-9_.-]*$)(?=^[^_].*[^_]$)"';
I used this snippet for my Laravel Validation so you may need to change the code as needed like " to / based on your code sample and other answers' code.
I'm pretty new on grails, I'm having a problem in matches validation using regex. What I wanted to happen is my field can accept a combination of alphanumeric and specific special characters like period (.), comma (,) and dash (-), it may accept numbers (099) or letters only (alpha) , but it won't accept input that only has special characters (".-,"). Is it possible to filter this kind of input using regex?
please help. Thank you for sharing your knowledge.
^[0-9a-zA-Z,.-]*?[0-9a-zA-Z]+?[0-9a-zA-Z,.-]*$
meaning:
/
^ beginning of the string
[...]*? 0 or more characters from this class (lazy matching)
[...]+? 1 or more characters from this class (lazy matching)
[...]* 0 or more characters from this class
$ end of the string
/
I think you could match that with a regular expression like this:
".*[0-9a-zA-Z.,-]+.*"
That means:
"." Begin with any character
"*" Have zero or more of these characters
"[0-9a-zA-Z.,-]" Have characters in the range 0-9, a-z, etc, or . or , or -
"+" Have one or more of this kind of character (so it's mandatory to have one in this set)
"." End with any character
"*" Have zero or more of these characters
This is working ok for me, hope it helps!