I have a directive for input on angular app.
I´m building a regex for accepting:
1,2,3.2
1222,23
333333
Not accepting:
1,,333
132,.1
-123
I have to check char by char, which that I´m not putting a whole number in input. My try that not work.
^[,]{0,1}\d{0,10}[,]{0,1}([.]?\d{0,2})
In the most general case you may use
^\d+(?:,\d+)*(?:\.\d+)?$ // 432 or 4.653 or 1,44,43211 or 1,4456,43211754.876597
See the regex demo and the regex graph:
Details
^ - start of string
\d+ - 1+ digits
(?:,\d+)* - 0 or more repetitions of , and 1+ digits
(?:\.\d+)? - 1 or 0 repetitions of . and 1+ digits
$ - end of string.
Use limiting quantifiers and lookaheads to impose length restrictions. For example:
^(?!(?:,?\d){6})\d+(?:,\d+)*(?:\.\d{1,3})?$
^^^^^^^^^^^^^^^
The (?!(?:,?\d){6}) negative lookahead will fail the match if there are 6 or more digits in the integer part of the number. If you want to restrict the whole number length change the lookahead to (?!.{6}) and it will only match numbers up to 5 chars: 1, 1.55, 35.99 but not 100.12 (=6 chars).
Related
I'm trying to find a regex for numeric inputs. We can receive a leading 0 just if we add a dot for adding 1 or 2 decimal numbers. And of course just accept numbers.
These are the scenarios that we can accept:
0.01
1.1
1.02
120.01
We can't accept these values
0023
0100
.01
.12
Which regex is the best option for these cases?
Until now we try we the following regex for accepting just number and dots
[A-Za-z,]
And also we try with the following ones:
^[+-]?[0-9]{1,3}(?:[0-9]*(?:[.,][0-9]{1})?|(?:,[0-9]{3})*(?:\.[0-9]{1,2})?|(?:\.[0-9]{3})*(?:,[0-9]{1,2})?)$
"/^[-]?[$]\d{1,3}(?:,?\d{3})*\.\d{2}$/"
"/(^(\d{1})\.{0,1}([0-9]){0,2}$)|(^([1-9])\d{0,2}(\,\d{0,3})$)/g"
(?:0|[1-9][0-9]*)(?:\.[0-9]{1,2})?
And the next one for deleting the leading zeros but it didn't work for 0.10 cases
^0+
If a negative lookahead is supported, you can exclude matches that start with a zero and have no decimal part.
^(?!0\d*$)\d+(?:\.\d{1,2})?$
^ Start of string
(?!0+\d*$) Negative lookahead, assert not a zero followed by optional digits at the right
\d+ Match 1+ digits
(?:\.\d{1,2})? Match an optional decimal part with 1 or 2 digits
$ End of string
Regex demo
I would go with ^(0|[1-9]\d*|(0|[1-9]\d*)\.\d+)$
You can test here: https://regex101.com/r/oNMgR9/1
Explanation
^ means : match the beginning of the string (or line if the m flag is enabled).
$ means : match the end of the string (or line if the m flag is enabled).
(a|b) means match "a" or match "b" so I'll use this to match either "0" alone or any number not starting with a "0". It's the syntax for a logical or.
. alone is used to match any char. So you have to escape it if you want to match the dot character. This is why I wrote 0\. instead of 0..
[ ] is used to list some characters you want to match. It can be a range if you use the - char, so [1-9] means any digit char from "1" to "9".
\d is to match a digit. It's totally equivalent to [0-9].
* means : match the preceding pattern 0 or many times, so \d* means that it will match 0 or many times a digit, so it will match "8" or "465" or "09" but also an empty string "". If you want to match the preceding pattern at least once or many times then you use + instead of *. So \d+ won't match an empty string "" but \d* would match it.
A) Just a number not starting with 0
[1-9]\d* will match any digit from 1 to 9 and then optionnaly followed by other digits. This will match numbers without a decimal point.
B) Just 0
0 alone is a possibility. This is because the case above isn't covering it.
B) A number with decimals
(0|[1-9]\d*)\.\d+ will match either a "0" alone or a number not starting by "0" and then followed by a point and some other digits (which have to be present because we don't want to match "45." without the numbers behind the dot).
Better alternative
The solution from #TheFourthBird is a bit cleaner with the use of a negative lookahead. It's just a bit different to understand. And he read the question completely: You wanted 1 or 2 digits after the decimal. I forgot about that, so, effectively, \d+ should be replaced by \d{1,2} as you don't want more than 2 digits.
You can use
^(?![0.]+$)(?:[1-9]\d*|0)(?:\.\d{1,2})?$
See the regex demo.
Details:
^ - start of string
(?![0.]+$) - fail the match if there are just zeros or dots till end of string
(?:[1-9]\d*|0) - either a non-zero digit followed with any zero or more digits or a zero
(?:\.\d{1,2})? - optionally followed with a sequence of a . and one or two digits
$ - end of string.
I am trying to block any strings that contain more than 3 numbers and prevent special characters. I have the special characters part down. I'm just missing the number part.
For example:
"Hello 1234" - Not Allowed
"Hello 123" - Allowed
I've tried the following:
/^[!?., A-Za-z0-9]+$/
/((^[!?., A-Za-z]\d)([0-9]{3}+$))/
/^((\d){2}[a-zA-Z0-9,.!? ])*$/
The last one is the closest I got as it prevents any special characters and any numbers from being entered at all.
I've looked through previous posts, but am coming up short.
Edit for clarification
Essentially I'm trying to find a way to prevent customers from entering PII on a form. No submission should be allowed that contains more than 3 numbers in a string.
Hello1234 - Not allowed
12345 - Not allowed
1111 - not allowed
No where in the comment section when the user enters the string should there be more than 3 numbers in total.
About the patterns that you tried
^[!?., A-Za-z0-9]+$ The pattern matches 1+ times any of the listed, including 1 or more digits
((^[!?., A-Za-z]\d)([0-9]{3}+$)) If {3}+ is supported, the pattern matches a single char from the character class, 1 digit followed by 3 digits
^((\d){2}[a-zA-Z0-9,.!? ])*$ The pattern repeats 0+ times matching 2 digits and 1 of the listed in the character class
You can use a negative lookahead if that is supported to assert not 4 digits in a row.
^(?!.*\d{4})[a-zA-Z0-9,.!? ]+$
regex demo
If there can not be 4 digits in total, but 0-3 occurrences:
^[a-zA-Z,.!? ]*(?:\d[a-zA-Z,.!? ]*){0,3}$
Explanation
^ Start of string
[a-zA-Z,.!? ]* Match 0+ times any of the listed (without a digit)
(?:\d[a-zA-Z,.!? ]*){0,3} Repeat 0 - 3 times matching a single digit followed by optional listed chars (Again without a digit)
$ End of string
regex demo
If you don't want to match an empty string and a lookahead is supported:
^(?!$)[a-zA-Z,.!? ]*(?:\d[a-zA-Z,.!? ]*){0,3}$
See another regex demo
Here is my two cents:
^(?!(.*\d){4})[A-Za-z ,.!?\d]+$
See the online demo
^ - Start string anchor.
(?! - Open a negative lookahead.
( - Open capture group.
.*\d - Match anything other than newline up to a digit.
){4} - Close capture group and match it 4 times.
) - Close negative lookahead.
[A-Za-z ,.!?\d]+ - 1+ Characters from specified class.
$ - End string anchor.
I think it should cover what you described.
Assuming you mean <= 3 digits, this may be a naive one but how about
[ALLOWED_CHARS]*[0-9]?[ALLOWED_CHARS]*[0-9]?[ALLOWED_CHARS]*[0-9][ALLOWED_CHARS]*?
Fill [ALLOWED_CHARS] to whatever you define is not special character and nums.
I created a Regex to check a string for the following situation:
first 4 chars are numbers
following by a point
following by 3 numbers
following by a point
following by 4 to 8 numbers or letters
ie: 1234.123.125B
My Regex: ^[0-9]{4}[.][0-9]{3}[.][0-9a-zA-Z]{4,8}$
But now I need a wildcard search: The Regex should also match if there is a '*' after the first 8 characters. For example:
1234.123.12* MATCH
1234.123* MATCH
1234.123.45B9* MATCH
1234.12* NO MATCH
1234.12345* NO MATCH
How can I add the wildcard search to my Regex?
Thank you
You may use this regex with alternation:
^\d{4}\.\d{3}(?:\*|\.[\da-zA-Z]{0,7}\*|\.[\da-zA-Z]{4,8})$
RegEx Demo
RegEx Details:
^: Start
\d{4}\.\d{3}: Match 4 digits + 1 dot + 3 digits
(?:\*|\.[\da-zA-Z]{0,7}\*|\.[\da-zA-Z]{4,8}): matches a single * OR a * after after a dot and 0 to 7 digits/letters OR match 4 to 8 digits/letters
$: End
My assumptions are that:
You don't allow wildcards to be mid-string
Nor do you want to allow wildcards after the full pattern (e.g.: 1234.123.12345678*).
So, alternatively you may possibily use something like:
^\d{4}\.\d{3}(?!.*\*.)(?![^*]{0,4}$)[.*][*\da-zA-Z]{0,8}$
See the online demo.
^ - Start string ancor.
\d{4}\.\d{3} - Four digits, a dot and another three digits.
(?!.*\*.) - Negative lookahead for zero or more characters followed by asterisk and another character other than newline.
(?![^*]{0,4}$) - Negative lookahead for zero to four characters other than asterisk before end string ancor.
[.*] - A literal dot or asterisk.
[*\da-zA-Z]{0,8} - Zero to eight characters from the character class.
$ - End string ancor.
So i got this regex code /[0-3][0-9][0-1][1-9]\d{2}[-\s]\d{4}?[^0-9]*|[0-3][0-9][0-1][1-9]\d{2}\d{4}/
This regex code take this kind of numbers:
1002821187
100282 1187
100282-1187
But i found out i dont want the numbers: 1002821187
So is it possible to make 1 regex code that only finds:
100282 1187
100282-1187
Your regex contains an alternation that matches the numbers with and without the space or -. You need to require that space or hyphen:
^[0-3][0-9][0-1][1-9][0-9]{2}[-\s][0-9]{4}$
^^^^^
See the regex demo. If you do not need to check for any boundaries, remove ^ and $ anchors that make the pattern match the whole string and use [0-3][0-9][0-1][1-9][0-9]{2}[-\s][0-9]{4}. Or use word boundaries to find whole words, \b[0-3][0-9][0-1][1-9][0-9]{2}[-\s][0-9]{4}\b.
Details
^ - start of string
[0-3] - a digit from 0 to 3
[0-9] - any digit
[0-1] (=[01]) - 0 or 1
[1-9] - any digit other than 0
[0-9]{2} - 2 digits
[-\s] - a - or whitespace
[0-9]{4} - 4 digits
$ - end of string.
Though you did not specify exactly what you are trying to do, here you can try the following regex :
\b\d{6}-\d{4}\b|\b\d{4}\b|\b\d{6}\b
Hope it helps.
I need regex that only allows a maximum of 2 digits (or whatever the desired limit is actually) to be entered into an input field.
The requirements for the field are as follows:
Allow a-z A-Z
Allow 0-9
Allow - and . characters
Allow spaces (\s)
Do not allow more than 2 digits
Do not allow any other special characters
I have managed to put together the following regex based on several answers on SO:
^(?:([a-zA-z\d\s\.\-])(?!([a-zA-Z]*\d.*){3}))*$
The above regex is really close. It works successfully for the following:
test 12 test
test12
test-test.12
But it allows an input of:
123 (but not 1234, so it's close).
It only needs to allow an input of 12 when only digits are entered into the field.
I would like some help in finding a more efficient and cleaner (if possible) solution than my current regex - but it must still be regex, no JS.
You could use a positive lookahead like
(?=^(?:\D*\d\D*){2}$) # only two digits
^[- .\w]+$ # allowed characters
See a demo on regex101.com.
You may use a negative lookahead anchored at the start that will make the match fail once there are 3 digits found anywhere in the string:
^(?!(?:[^0-9]*[0-9]){3})[a-zA-Z0-9\s.-]*$
^^^^^^^^^^^^^^^^^^^^^^^
See the regex demo
Details:
^ - start of string
(?!(?:[^0-9]*[0-9]){3}) - the negative lookahead failing the match if exactly 3 following sequences are found:
[^0-9]* - zero or more chars other than digits
[0-9] - a digit (thus, the digits do not have to be adjoining)
[a-zA-Z0-9\s.-]* - 0+ ASCII letters, digits, whitespace, . or - symbols
$ - end of string.