How to validate both integer and decimal values using regular expression?

Question

Tring Allow to both Integer as well as Decimal as input. And restricting on total length which should not be greater that 11(MaximumLength of input including decimal point) eg. Allowed values are 1.0, 1.123546, 12345678912,12.12345678,...etc. i.e. If value contain Decimal point then allow at least one digit after Decimal point otherwise allow complete integer number with maximum length i.e. 11

I have declared regular expression as: /^-?(([0-9]{0,11}) | ([0-9]{0,9}.[0-9]{1,2}))$/

And the values I'm testing against as: 6666666.666

But the result always not getting matched.

NOTE: If length of digit before decimal point is 7 then allow 3 digit after decimal point in case Maximum allowed length is 11. Fractional part length decided based on integral part.

------------------------ JQuery Function-----------------------------------

function Validate(sender, precision)
{
    var variable;
    if (precision != "0") 
    {
        var valueLength = sender.value.indexOf('.');
        if (sender.id.indexOf("Longitude") > -1)
            variable = "-?[0-9,]{0," + parseInt($(sender).attr("data-length") - (parseInt(precision) + 1)) + "}[.][0-9]{0," + parseInt(precision) + "}$";
        else
        variable = "-?(([0-9]{0," + parseInt($(sender).attr("data-length")) + "})|([0-9]{0," + parseInt($(sender).attr("data-length") - 2) + "}.[0-9]{1," + parseInt

        ($(sender).attr("data-length") - (valueLength + 2)) + "}))$";
    }
    else
        variable = "-?[0-9,]{0," + parseInt($(sender).attr("data-length")) + "}$";
        var re = new RegExp('^' + variable);
    if (sender.value != "") 
    {
        if (!re.test(sender.value)) 
        {
            alert('Not Matched');
        }
        else
        {
            alert('Matched');
        }
    }

}

Are the spaces around the alternation a copy/paste error? if not, remove them. — Sebastian Proske
– Sebastian Proske, Commented Mar 22, 2016 at 9:40
Why not check the length separately? if ((sender.value+"").length <= 11) — fdomn-m
– fdomn-m, Commented Mar 22, 2016 at 9:40

Community · Accepted Answer · 2017-05-23 12:14:45Z

2

If you want to use regex only, an idea is to use a negative lookahead for checking max length.

^-?(?!.{12})\d+(?:\.\d+)?$

^-? an optional hyphen at ^ start
(?!.{12}) the lookahead checks if there's not more than 11 of any characters ahead.
\d+ matches one or more \d which is a short for digit [0-9]
(?:\.\d+)? followed by an optional group containing a dot followed by one or more digits.
$ matches the end

See demo at regex101

edited May 23, 2017 at 12:14

CommunityBot

11 silver badge

answered Mar 22, 2016 at 11:09

bobble bubble

18.8k4 gold badges32 silver badges52 bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

Kaishu Over a year ago

I have insert above mentioned expression in function I've put above but still re.test(sender.value) always returning false...

bobble bubble Over a year ago

@Kaishu Try /^-?(?!.{12})\d+(?:\.\d+)?$/.test(sender.value) works fine (fiddle).

Kaishu Over a year ago

this works, so what is the problem in function where I'm using this.?

bobble bubble Over a year ago

@Kaishu If you use with new RegExp need more escaping: var re = new RegExp('^-?(?!.{12})\\d+(?:\\.\\d+)?$'); see fiddle.

VoteyDisciple · Accepted Answer · 2016-03-22 09:42:00Z

2

First, . is a special character in a regular expression which matches any character, so your expression matches more than you're expecting.

More importantly, you're explicitly looking for {0,9} characters before the decimal and {0,2} after it, and the example you gave of 6666666.666 has more than two decimals.

Why not simply

if (/^[0-9]+(\.[0-9]+)?$/.test( sender.value ) && sender.value.length <= 11) ...

Let the regex worry about the numbers and formatting and deal with the length separately. Length is easy to check without mucking around with regex variations.

answered Mar 22, 2016 at 9:42

VoteyDisciple

37.9k5 gold badges100 silver badges100 bronze badges

4 Comments

Kaishu Over a year ago

This is ok for other fields but there are another fields like latitude and longitude where I'm restricting user with the format as 99.999999999 and 999.999999999999 respectively but this condition allows those fields to take integral part more that 2 and three digit for lat and long... How to handle these combine condition.?

VoteyDisciple Over a year ago

You cannot have a single test for both "any number of digits before or after the decimal as long as the total length is 11 or fewer characters" and "any number of characters long but with only two or three digits before the decimal". Write one test for one and a completely separate test for the other. (In the latter case it's /^[0-9]{2,3}(\.[0-9]+)$/)

Kaishu Over a year ago

I don't know why it allowing value as (111.) . As we have restricted to insert atleast one digit after decimal point still it allows empty fractional part after decimal point.

VoteyDisciple Over a year ago

My expression explicitly ends with ? so the decimal component is not required. If you need it to be required, don't use a ? there.

Collectives™ on Stack Overflow

How to validate both integer and decimal values using regular expression?

2 Answers 2

4 Comments

4 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

4 Comments

4 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related