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RegEx to allow hyphens (maximum 3) in a string but do not count it in length

My requirement is to limit the length of the input string to 11 which can be alphanumeric with hyphens. The maximum allowable hyphens are 3 and hyphens shouldn’t be considered in length. Another requirement is to not allow more than 5 continuous repetitive digits.
My Regex is ^(?!.*([0-9])\\1{5})(?=.*([-]){0,3})[a-zA-Z0-9]{11}$

Well, one way is:
^(?!.*?(\d)\1{5})(?=(?:[a-z0-9]-?){11}$)[a-z0-9]+(?:-[a-z0-9]+){0,3}$
See an online demo
^ - Start-line anchor;
(?!.*?(\d)\1{5}) - Negative lookahead to assert input has no digit that is repeated 6 times;
(?=(?:[a-z0-9]-?){11}$) - Positive lookahead to assert input has 11 alphanumeric characters (with optional hyphens);
[a-z0-9]+(?:-[a-z0-9]+){0,3} - 1+ Alnum chars followed by a non-capture group (0-3 times) to allow for hyphens;
$ - End-line anchor.
Note that it would not allow for hyphens to be at either: start, end or consecutive. Further note that I used the case-insensitive flag.

Regular expression that accepts only two digit integer or a floating number

I am trying to validate a text field that accepts number like 10.99, 1.99, 1, 10, 21.
\d{0,2}\.\d{1,2}
Above expression is only passing values such as 10.99, 11.99,1.99, but I want something that would satisfy my requirement.

Try this:
^\d{1,2}(\.\d{1,2})?$
^ - Match the start of string
\d{1,2} - Must contains at least 1 digit at most 2 digits
(\.\d{1,2}) - When decimal points occur must have a . with at least 1 and at most 2 digits
? - can have zero to 1 times
$ - Match the end of string

Assuming you don't want to allow edge cases like 00, and want at least 1 and at most 2 decimal places after the point mark:
^(?!00)\d\d?(\.\d\d?)?$
This precludes a required digit before the decimal point, ie ".12" would not match (you would have to enter "0.12", which is best practice).
If you're using String#matches(), you can drop the leading/trailing ^ and $, because that method must to match the entire string to return true.

First \d{0,2} does not seem to fit your requirement as in that case it will be valid for no number as well. It will give you the correct output but logically it does not mean to check no number in your string so you can change it to \d{1,2}
Now, in regex ? is for making things optional, you can use it with individual expression like below:
\d{1,2}\.?\d{0,2}
or you can use it on the combined expression like below
\d{1,2}(\.\d{1,2})?
You can also refer below list for further queries:
abc… Letters
123… Digits
\d Any Digit
\D Any Non-digit character
. Any Character
\. Period
[abc] Only a, b, or c
[^abc] Not a, b, nor c
[a-z] Characters a to z
[0-9] Numbers 0 to 9
\w Any Alphanumeric character
\W Any Non-alphanumeric character
{m} m Repetitions
{m,n} m to n Repetitions
* Zero or more repetitions
+ One or more repetitions
? Optional character
\s Any Whitespace
\S Any Non-whitespace character
^…$ Starts and ends
(…) Capture Group
(a(bc)) Capture Sub-group
(.*) Capture all
(abc|def) Matches abc or def
Useful link : https://regexone.com/

Can you try using this :
(\d{1,2}\.\d{1,2})|(\d{1,2})
Here is a Demo, you can check also simple program
You have two parts or two groups one to check the float numbers #.#, #.##, ##.##, ##.# and the second group to check the integer #, ##, so we can use the or |, float|integer

I think patterns of this type are best handled with alteration:
/^\s*([-+]?[0-9]*\.[0-9]+([eE][-+]?[0-9]+)?)$ #float
| # or
^(\d{1,2})$ # 2 digit int/mx
Demo

regular expression not containing two or more consecutive comma or hyphen and between numbers at most one hyphen

I have scenario to validate number range, it can be multiple range or single number.
Ex number 1 to 10 can be written as (1-3,4,5-8,9,10) here 1-3 indicates rage (1,2,3) I have tried java regex :
Pattern.matches("^[0-9][0-9,-]*,[0-9,-]*[0-9]$","11,131-132-134,45,12--10,,10");
this pattern allows consecutive hyphen and comma,
Valid Input
1) 1-3,4,5-8,9,10
2) 1-3,4-5,6-10
3) 1,2,3,4,5
4) 1,2-5,6
Invalid Input
1) ,2,3,4-10,
2) -2,3,4-10-
3) 2,3,,4-10
4) 2,3,4--10
5) 2,3,4-6-10 (Invalid range)
can someone suggest how to check the comma and hyphen should not appear two times consecutively, start and end with number, range should not repeat (4-8-10)

This should be the regex you want:
^\\d+(-\\d+)?(,\\d+(-\\d+)?)*$
It checks for the following sequence:
\\d+ : One or more digits
(-\\d+)? : An optional sequence of hyphen followed by one or more digits
(,\\d+(-\\d+)?)* : Zero or more occurrence of a comma followed by one or more digits followed by an optional sequence of hyphen followed by one or more digits
As the regex looks for a digit at the beginning, a string starting with hyphen or comma will not be allowed.
As it looks for a digit to be immediately followed by a hyphen and comma, a string having consecutive hyphens or commas, a hyphen immediately followed by a comma or the reverse would not be allowed.
As the ? in (-\\d+)?allows exactly zero or one occurrence of the (-\\d+) sequence, a range like 1-2-3 will not be matched.
If you don't need to allow a single number alone, replace the * in ^\\d+(-\\d+)?(,\\d+(-\\d+)?)*$ with +.

A repeated group is a simple way to validate a string of a repeating sequence:
(?:\\d+(?:-\\d+)?,)+(?:\\d+(?:-\\d+)?$)
Live demo

Regex to allow only 10 or 16 digit comma separated number

I want to validate a textfield in a Java based app where I want to allow only comma separated numbers and they should be either 10 or 16 digits. I have a regex that ^[0-9,;]+$ to allow only numbers, but it doesn't work for 10 or 16 digits only.

You can use {n,m} to specify length.
So matching one number with either 10 or 16 digits would be
^(\d{10}|\d{16})$
Meaning: match for exactly 10 or 16 digits and the stuff before is start-of-line and the stuff behind is end-of-line.
Now add separator:
^((\d{10}|\d{16})[,;])*(\d{10}|\d{16})$
Some sequences of 10-or-16 digit followed by either , or ; and then one sequece 10-or-16 with end-of-line.
You need to escape those \ in java.
public static void main(String[] args) {
String regex = "^((\\d{10}|\\d{16})[,;])*(\\d{10}|\\d{16})$";
String y = "0123456789,0123456789123456,0123456789";
System.out.println(y.matches(regex)); //Should be true
String n = "0123456789,01234567891234567,0123456789";
System.out.println(n.matches(regex)); //should be false
}

I would probably use this regex:
(\d{10}(?:\d{6})?,?)+
Explanation:
( - Begin capture group
\d{10} - Matching at least 10 digits
(?: - Begin non capture group
\d{6} - Match 6 more digits
)? - End group, mark as optional using ?
,? - optionally capture a comma
)+ - End outer capture group, require at least 1 or more to exist? (mabye change to * for 0 or more)
The following inputs match this regex
1234567890123456,1234567890
1234567890123456
1234567890
these inputs do not match
123,1234567890
12355
123456789012

You need to have both anchors and word boundaries:
/^(?:\b(?:\d{10}|\d{16})\b,?)*$/
The anchors are necessary so you don't get false positives for partial matches and the word boundaries are necessary so you don't get false positives for 20, 26, 30, 32 digit numbers.

Here is my version
(?:\d+,){9}\d+|(?:\d+,){15}\d+
Let's review it. First of all there is a problem to say: 10 or 16. So, I have to create actually 2 expressions with | between them.
Second, the expression itself. Your version just says that you allow digits and commas. However this is not what you really want because for example string like ,,, will match your regex.
So, the regex should be like (?:\d+,){n}\d+ that means: sequence of several digits terminated by comma and then sequence of several digits, e.g. 123,45,678 (where 123,45 match the first part and 678 match the second part)
Finally we get regex that I have written in the beginning of my answer:
(?:\d+,){9}\d+|(?:\d+,){15}\d+
And do not forget that when you write regex in you java code you have to duplicate the back slash, like this:
Pattern.compile("\\d+,{9}\\d+|\\d+,{15}\\d+")
EDIT: I have just added non-capturing group (?: ...... )

validate decimal with decimal separator and thousand separator

Hi I used this regex for validate number with decimal separator and thousand separator
ets = "\\,";
eds = "\\.";
"^([+\\-]?[0-9" + ets + "]*(" + eds + "[0-9]*)?)$"
But this fail (it accept when it should not) for two of my unit test case,
12., and 1,,2, anyone can help please?
Note: This work for 1..2.

Let's look at the actual regex that is used:
^([+\-]?[0-9\,]*(\.[0-9]*)?)$
This matches 12. because your second part is (\.[0-9]*). Note that * means zero or more, so digits are optional.
This also matches 1,,2 because you included the comma in the first character class [0-9\,]. So actually your regex would match ,,,,,,,, as well.
This can be solved without regexes, but if you need a regex, you'd probably want something like this:
^[+-]?[0-9]{1,3}(,[0-9]{3})*(\.[0-9]+)?$
Broken down:
^ # match start of string
[+-]? # matches optional + or - sign
[0-9]{1,3} # match one or more digits
(,[0-9]{3})* # match zero or more groups of comma plus three digits
(\. # match literal dot
[0-9]+ # match one or more digits
)? # makes the decimal portion optional
$ # match end of string
To use this in Java you'd want something like:
ets = ","; // commas don't need to be escaped
eds = "\\."; // matches literal dot
regex = "^[+-]?[0-9]{1,3}(" + ets + "[0-9]{3})*(" + eds + "[0-9]+)?$"

If I understand correctly, 12. matches because you are matching 0 or 1 occurences of (a period, then 0 or more ocurrences of any number between 0 and 9). So you may have a period and nothing in front of it.
1,,2 matches because you are matching 0 or more occurences of any characters between 0 and 9, or a comma. therefor you could have 0,,,,,,,,,,,,,,0.
If you want the last one not to match, make sure you can only have up to 3 numbers before a comma (in the thousand separator) using curly braces to indicate the amount of ocurrences allowed (i. e. {0,3}) after a set of numbers.
[0-9]{0,3},
#NullUserException just gave a complete regexp that works for your intentions