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Regex to match numbers between 0 to 25 both inclusive which can be doubles with 1 precision

I want to use Regex to match numbers between 0 to 25 both inclusive which can be doubles with 1 precision.
For ex.- 2, 2.5, 23.0, 8, 24.3, 25
I created following regex-
^(\\s*|0?[0-9]|[0-9]|1[0-9]|2[0-5])$
But it works only for numbers between 0 to 25 both inclusive.

This is the regex pattern I would use here:
^(?:(?:[0-9]|1[0-9]|2[0-4])(?:\.[0-9])?|25(?:\.0)?)$
Demo
The pattern is similar to what you used, except that we only match 2[0-4] with any single decimal point. The end point 25 is a special case, which can only take 25.0 at most for its decimal component.
But in general it would easier in JavaScript to just parse the text number, and then use an inequality to check the range. E.g.
var number = '24.3'
if (number >= 0 && number <= 25.0) {
console.log('within range');
}

To verify the validity, use the >= and <= operators. To meet the regex requirement, just add a garbage regex expression.
let isMatch = number => {
'must use regex'.match(/x/);
return number >= 0 && number <= 25;
};

JavaScript regex two string number separated by ( : ) individual max min calculation

I need to validate JavaScript string like "03:39" with Regex. Rules are following,
1.First part of the string which is before (:) is allowed from 0 to 24
2.Second part of the string which is after (:) is allowed from 0 to 59
3.Single digit number of both part can either be start with 0 like 01 or 02 or with out 0 like 1 , 2.
Now i have wrote a JavaScript regex code which is following.
var dateRegEx = /^n(0[0-2][0-4]|[0-24])(:)(0|[0-5][0-9]|[0-59])$/;
if ($(element).val().match(dateRegEx) === null) {
// my rest of the code
}
now, when user insert 0:38, 01:38 or 02:59 it get validated but when the first part incensed after 2 like 03:38 it not validating the string.
So what am i doing wrong ??

For hours, your current 0[0-2][0-4] requires three digits (none of which can be above 4), whereas [0-24] will only match one digit (a 0, 1, 2, or 4).
Rather, to match hours (00 to 24), you should use (?:2[0-4]|[01]?[0-9]); either a 2 followed by a number from 0 to 4, or an (optional) 0 or 1 followed by any other digit.
To match minutes (00 to 59), use [0-5]?[0-9] - an optional digit from 0 to 5, followed by a digit from 0 to 9.
^(?:2[0-4]|[01]?[0-9]):[0-5]?[0-9]$
https://regex101.com/r/0QxX7w/1
Note that if you're just matching a single character like :, don't put it in a character set. Also, because you don't want an n at the beginning of the match, remove it from the beginning of your pattern.

Well i think you don't need regex here you can do directly like this
function check(input){
let temp = input.split(':')
return (0 <= temp[0] && temp[0] <=24 ) && ( 0<= temp[1] && temp[1] <=59)
}
console.log(check('03:380'))
console.log(check('03:38'))
console.log(check('30:0'))
With regex you can do it like this
function check(input){
return /^(?:[01]?[0-9]|[0-2][0-4]):[0-5]?[0-9]$/.test(input)
}
console.log(check('03:30'))
console.log(check('03:380'))
console.log(check('33:30'))
console.log(check('24:59'))
console.log(check('03:60'))
console.log(check('0:0'))
console.log(check('0:30'))

JavaScript RegExp to automatically format Pattern

I have seen a lot of functions that format telephone or number (comma and decimals) in stackflow community like this question here and others. Here's what I want to:
Step 1: Maintain a Library for patterns like this:
var library = {
fullDate : {
pattern : /^[0-9]{4}-[0-9]{1,2}-[0-9]{1,2}$/,
error : "Invalid Date format. Use YYYY-MM-DD format."
},
fullDateTime : {
pattern : /^[0-9]{4}-[0-9]{1,2}-[0-9]{1,2} [0-9]{1,2}:[0-9]{1,2}$/,
error : "Invalid DateTime format. Use YYYY-MM-DD HH:MM (24-hour) format."
},
tel : {
pattern : /^\(?([0-9]{3})\)?[-. ]?([0-9]{3})[-. ]?([0-9]{4})$/,
error : "Invalid Telephone format."
}
};
Step 2: Automatically add a character as they type. For exapmple, add a - after 4 numbers in Date.
I have a text field say:
<input type="text" data-validate="fullDate" placeholder="YYYY-MM-DD"/>
And possible place to start script as:
$('body').on('keyup','input',function(){
var validate = $(this).data('validate');
var pattern = library[validate].pattern;
//Some more steps here....
});
But, I cannot make any further because I am new to RegExp. Here's a startup fiddle. Anyone?
Further Notes: I have been able to validate using the following functions but what I want to is automatically make pattern:
function validate(libraryItem, subject){
var item = library[libraryItem];
if(item !== undefined){
var pattern = item.pattern;
if(validatePattern(pattern, subject)){
return true;
} else {
return item.error;
}
}
return false;
}
function validatePattern(pattern, subject){
return pattern.test(subject);
}

It is not as complicated as you think. What you are looking for is JQuery Masked input and other alternative libraries. Here is the documentation. All you need is:
<input id="date" type="text" placeholder="YYYY-MM-DD"/>
and the script:
$("#date").mask("9999-99-99",{placeholder:"YYYY-MM-DD"});
Here is demo pen link:
http://codepen.io/anon/pen/gpRyBp
To implement validation use this library:
https://github.com/RobinHerbots/jquery.inputmask

What needed here is breaking up the regular expression in sub expression which matches part of the string and suggest completion based upon next character in the Regular Expression.
I wrote a naive Parser which parses the expression and divides into atomic subexpression.
var parser = function(input) {
var tokenStack = [];
var suggestions = [];
var suggestion;
var lookAhead;
if (input[0] === '/')
input = input.slice(1, input.length - 1);
var i;
for (i = 0; i < input.length - 1; i++) {
lookAhead = input[i + 1];
switch (input[i]) {
case '(':
tokenStack.push('(');
break;
case '[':
tokenStack.push('[');
break;
case ')':
if (tokenStack[tokenStack.length - 1] === '(') {
tokenStack.pop();
if (tokenStack.length === 0) {
suggestion = generateSuggestion(input, i);
if (suggestion !== null)
suggestions.push(suggestion);
}
}
else
throw 'bracket mismatch';
break;
case ']':
if (lookAhead === '{') {
while (input[i] !== '}')
i++;
}
if (tokenStack[tokenStack.length - 1] === '[') {
tokenStack.pop();
if (tokenStack.length === 0) {
suggestion = generateSuggestion(input, i);
if (suggestion !== null)
suggestions.push(suggestion);
}
}
else
throw 'bracket mismatch';
break;
default:
if (tokenStack.length === 0) {
suggestion = generateSuggestion(input, i);
if (suggestion !== null)
suggestions.push(suggestion);
}
break;
}
}
return suggestions;
}
var generateSuggestion = function(input, index) {
if (input[index].match(/[a-zA-Z\-\ \.:]/) !== null)
return {
'regex': input.slice(0, index) + '$',
'suggestion': input[index]
};
else
return null;
}
Here is sample input and output of parser()
parser('/^[0-9]{4}-[0-9]{1,2}-[0-9]{1,2}$/');
// output:
[ { regex: '^[0-9]{4}$', suggestion: '-' },
{ regex: '^[0-9]{4}-[0-9]{1,2}$', suggestion: '-' } ]
Thus on every keyup you need to check the list of RegExp generated by parser and if any of it matches the input then use the suggestion.
EDIT:
Edited generateSuggestion to match only full expression.
Here is sample fiddle: http://jsfiddle.net/a7kkL6xu/6/
With backspace ignored: http://jsfiddle.net/a7kkL6xu/7/

This could be done with a single regex.
This requires a MM:DD and HH:MM to be 2 digits and YYYY to be 4 digits on a
fully valid entry, but matches all the partials.
It could be made to allow a single digit validity for the 2 digit valid mentioned.
But doing so, will make premature suggestions on the - - [ ] : form.
If you want to not inject the suggestion, then 1 or 2 digits is fine.
JavaScript doesn't allow lookbehind assertions, so partial field expressions
are below the valid field expressions in their respective groups.
Basically what happens is the input is rewritten on each key press event.
All you do is match the current input within the event handler.
Without suggestions, you just write over the input with the entire match (group 0).
The match (group 0) will only contain a valid partial or full match.
The valid completed field capture groups are 1 through 5
[ Year, Month, Day, Hours, Minutes ]
The incomplete field captures are groups 6 through 10
[ Minutes, Hours, Day, Month, Year ]
This is the logic:
// Note 1 - can handle control chars by just returning.
// Note 2 - can avoid rewrite by keeping a global of last good,
// then return if current == last.
if ( last char of group 0 is a dash '-' or space ' ' or colon ':'
or any of groups 6 - 10 matched
or group 5 matched )
set input equal to the group 0 string;
else if ( group 4 matched ) // Hours
set input equal to group 0 string + ':';
else if ( group 3 matched ) // Day
set input equal to group 0 string + ' ';
else if ( group 1 or 2 matched ) // Year or Month
set input equal to group 0 string + '-';
else // Here, effectively strips bad chars from input box
// before they are displayed.
set input equal to group 0 string;
Note that if a group didn't match it's value will be NULL
and to check the entire validity, there should be no partials and
groups 1 - 3 must be complete for just YYYY-MM-DD or 1 - 5 with the optional
time HH:MM
Final Note: This is a parser, and effectively a test case of the look and feel, ie. flicker, of real time input rewrite.
If it goes well, the logic in the handler can include Day validation (and rewrite) based on the month.
Also, the premise can be expanded to any type of input, any type of form and
form delimiter combinations, etc..
If it works, you can build a library.
# /^(?:(19\d{2}|20[0-1]\d|202[0-5])(?:-(?:(0[1-9]|1[0-2])(?:-(?:(0[1-9]|[1-2]\d|3[0-1])(?:[ ](?:(0\d|1\d|2[0-3])(?::(?:(0\d|[1-5][0-9])|([0-5]))?)?|([0-2]))?)?|([0-3]))?)?|([01]))?)?|(19\d?|20[0-2]?|[12]))/
^ # BOL
(?:
( # (1 start), Year 1900 - 2025
19 \d{2}
| 20 [0-1] \d
| 202 [0-5]
) # (1 end)
(?:
- # -
(?:
( # (2 start), Month 00 - 12
0 [1-9]
| 1 [0-2]
) # (2 end)
(?:
- # -
(?:
( # (3 start), Day 00 - 31
0 [1-9]
| [1-2] \d
| 3 [0-1]
) # (3 end)
(?:
[ ] # space
(?:
( # (4 start), Hour 00 - 23
0 \d
| 1 \d
| 2 [0-3]
) # (4 end)
(?:
: # :
(?:
( # (5 start), Minutes 00 - 59
0 \d
| [1-5] [0-9]
) # (5 end)
|
( [0-5] ) # (6)
)?
)?
|
( [0-2] ) # (7)
)?
)?
|
( [0-3] ) # (8)
)?
)?
|
( [01] ) # (9)
)?
)?
|
( # (10 start)
19 \d?
|
20 [0-2]?
|
[12]
) # (10 end)
)

It is only possible to add a character if it is the single possible choice at this point. An example would be a regex for the YYYY-MM-DD HH24:mm format: the -, the : and the (space) could be added. Here is the corresponding regex (/ ommitted to make it more readable, it is stricter than the one in the question, some illegal dates are still possible like 31st of February):
^[0-9]{4}-(?:0[1-9]|1[0-2])-(?:0[1-9]|[12][0-9]|3[01]) (?:[01][0-9]|2[0-3]):[0-5][0-9]$
For fixed length inputs you could use #DineshDevkota's solution to add the literals and verify the whole text with regex. I think it's the cleanest and simplest solution. You could also capture the year, month and day to verify the day mathematically. Also rules like "date not in the future" or "max. 100 years in past" can only be veryfied in JS and not with just regex.
The only additional patterns that come to mind where a character could be automatically added:
A + after a literal, e.g. on A+ add an A
Minimal occurances in general, e.g. on (?:foo){2,5} add foofoo not to be confused with [fo]{2,5} where no characters can be added
Literals after the max length of a variable part, e.g. on (?:foo){1,3}bar add bar after the text is foofoofoo before it is not possible.
Add remainders e.g. foo|bar add ar when b was typed and oo when f was typed (also possible in the pattern shown in 3.) but this won't work for ^[a-z]+?(?:foo|bar)$ because we don't know when the user plans on ending the text and it can get really complicated (foo|flo|flu|food|fish only sh can be added after fi).
As seen in 3. and 4. those additional cases where characters could be added are of very limited use as soon as there are parts with variable length. You would have to parse the regex, split it in literal and regex parts. Then you have to parse/analyse the regex parts to incorporate the additional cases mentioned above where characters could be added. Really not worth the trouble if you ask me. (Not a single character can be added in your tel pattern.)

JQuery validate regular expression to get interest rate

I want regular expression to get rate of interest. I am wanting to accept following things:
Ex:
0
0.4
0.44
4
44
4.00
44.00
4.2
4.22
44.22
Min 0 and Max 99.99
It must have to accept numeric as well as decimal values but not more than 99.99. Also it should take decimal after first or second digit and after third digit it should display an error message.
I am trying this regular expression but its not perfectly working for me.
$.validator.addMethod('interest', function(value, element) {
return this.optional(element) || /\d{1,2}\.?\d{0,4}/.test(value);
}, 'Please specify a valid data');
Any help would be appreciated.

A regex to match all of those numbers between 0 and 99.99 would be:
^\d{1,2}(\.\d{1,2})?$
so you're pretty close, but your regex matches 0 to 4 digits after the .
EDIT: forgot ^$

Why mess with regexes if you can simply check for the value:
var input = parseFloat(value)
return !isNaN(input) && input >= 0 && input < 100;
If you want to make sure there are at most 2 decimal placed in the string, the check will be a little longer:
return !isNaN(input) &&
input >= 0 &&
input < 100 &&
!(value.split('.')[1] && value.split('.')[1].length > 2);

If you use regex you will end up having two problems. Try:
function validateStuff(input) {
return ($.isNumeric(input) && input >= 0 && input <= 99.99);
}
// Testing:
console.log(validateStuff(5));
console.log(validateStuff("Hello"));
console.log(validateStuff(100));
console.log(validateStuff(99.99));
DEMO

Integer Comparison

I need to compare two Integers which could exceed Integer range limit. How do I get this in javascript.
Initially, I get the value as String, do a parseInt and compare them.
var test = document.getElementById("test").value;
var actual = document.getElementById("actual").value;
if ( parseInt(test) == parseInt(actual)){
return false;
}
Any options to use long ? Also, which is best to use parseInt or valueOf ??
Any suggestions appreciated,
Thanks

You'd better to assign the radix. Ex. parseInt('08') will give 0 not 8.
if (parseInt(test, 10) === parseInt(actual, 10)) {

Leave them in String and compare (after you have cleaned up the string of leading and trailing spaces, and other characters that you consider safe to remove without changing the meaning of the number).
The numbers in Javascript can go up to 53-bit precision. Check whether your number is within range.
Since the input is expected to be integer, you can be strict and only allow the input to only match the regex:
/\s*0*([1-9]\d*|0)\s*/
(Arbitrary leading spaces, arbitrary number of leading 0's, sequence of meaningful digits or single 0, arbitrary trailing spaces)
The number can be extract from the first capturing group.

Assuming integers and that you've already validated for non-numeric characters that you don't want to be part of the comparison, you can clean up some leading/trailing stuff and then just compare lengths and if lengths are equal, then do a plain ascii comparison and this will work for any arbitrary length of number:
function mTrim(val) {
var temp = val.replace(/^[\s0]+/, "").replace(/\s+$/, "");
if (!temp) {
temp = "0";
}
return(temp);
}
var test = mTrim(document.getElementById("test").value);
var actual = mTrim(document.getElementById("actual").value);
if (test.length > actual.length) {
// test is greater than actual
} else if (test.length < actual.length) {
// test is less than actual
} else {
// do a plain ascii comparison of test and actual
if (test == actual) {
// values are the same
} else if (test > ascii) {
// test is greater than actual
} else {
// test is less than actual
}
}