RegEx validation of decimal numbers with comma or dot

Question

How to validate such number input with one RegEx. Strings are not allowed. Two decimal positions after dot or comma.

Example:

123.34
1.22
3,40
134,12
123

possible duplicate of [Decimal or numeric values in regular expression validation](http://stackoverflow.com/questions/2811031/decimal-or-numeric-values-in-regular-expression-validation) — JJJ, Oct 25 '11 at 08:30

score 26 · Accepted Answer · answered Oct 25 '11 at 08:36

26

Try this regex:

/^(\d+(?:[\.\,]\d{2})?)$/

If $1 exactly matches your input string then assume that it is validated.

answered Oct 25 '11 at 08:36

Aziz Shaikh

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11
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How to allow passing null value in this expression? – thesis Oct 25 '11 at 11:01
For null values, try this updated regex: `^(\d+(?:[\.\,]\d{2})?|)$`. Basically added a `|` towards the end. – Aziz Shaikh Oct 25 '11 at 11:06
Thank you! That works for decimals, but not for normal integers, like: ex. 453 – thesis Oct 25 '11 at 11:09
That is strange. I have tested the regex [here on JSFiddle for the demo](http://jsfiddle.net/PLBex/). – Aziz Shaikh Oct 25 '11 at 11:38

score 9 · Answer 2 · edited Apr 08 '15 at 12:04

9

Try This,

/^(\d+(?:[\.\,]\d{1,2})?)$/

edited Apr 08 '15 at 12:04

Michel Ayres

5,891
10
63
97

answered Jan 27 '15 at 11:04

Om Infowave Developers

1,525
15
40

Melchia · Answer 3 · 2020-04-20T13:11:15.707

2

This is my method to test decimals with , or . With two decimal positions after dot or comma.

(\d+) : one or more digits
(,\d{1,2}|\.\d{1,2})? : use of . or , followed by 2 decimals maximum

const regex = /^(\d+)(,\d{1,2}|\.\d{1,2})?$/;

console.log("0.55 returns " + regex.test('0.55')); //true
console.log("5 returns " + regex.test('5')); //true
console.log("10.5 returns " + regex.test('10.5')); //true
console.log("5425210,50 returns " + regex.test('5425210,50')); //true

console.log("");

console.log("10.555 returns " + regex.test('10.555')); //false
console.log("10, returns " + regex.test('10,')); //false
console.log("10. returns " + regex.test('10.')); //false
console.log("10,5.5 returns " + regex.test('10,5.5')); //false
console.log("10.5.5 returns " + regex.test('10.5.5')); //false

edited Apr 20 '20 at 13:11

answered Mar 19 '20 at 16:44

Melchia

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`const regex = /^(\d+)(,\d{2}|\.\d{2})?$/;` is better as it allows only 2 digits after the dot or comma. – thiebo Jun 09 '22 at 04:39
@thiebo but what about only one digit after the dot? – Melchia Jun 09 '22 at 08:08
that was not the question. – thiebo Jun 09 '22 at 09:42

score 2 · Answer 4 · answered Oct 25 '11 at 08:35

2

pat = re.compile('^\d+([\.,]\d\d)?$')
re.match(pat, '1212')
<_sre.SRE_Match object at 0x91014a0>
re.match(pat, '1212,1231')
None
re.match(pat, '1212,12')
<_sre.SRE_Match object at 0x91015a0>

answered Oct 25 '11 at 08:35

spicavigo

4,116
22
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is that python? – nurettin Dec 02 '17 at 17:18

score 0 · Answer 5 · answered Dec 12 '21 at 20:29

Private Sub TexBox_TextChanged(sender As Object, e As EventArgs) Handles TexBox.TextChanged

    TexBox.Text = System.Text.RegularExpressions.Regex.Replace(TexBox.Text, "[^\d\.]", "")

    TexBox.Select(TexBox.Text.Length + 1, 1)

    Dim x As Integer = 0

    For Each c In TexBox.Text
        If c = "." Then
            x += 1

            If (x > 1) Then
                TexBox.Text = TexBox.Text.Substring(0, TexBox.Text.Length - 1)
                TexBox.Select(TexBox.Text.Length + 1, 1)
            End If


        End If
    Next

End Sub

score 0 · Answer 6 · answered May 21 '22 at 15:00

A more precise validation over thousands separator and prefix signal:

const re = /^[-\\+]?\s*((\d{1,3}(,\d{3})*)|\d+)(\.\d{2})?$/
console.log(re.test('-1000000.00')) // true
console.log(re.test('-1,000,000.00')) // true
console.log(re.test('-1000,000.00')) // false

RegEx validation of decimal numbers with comma or dot

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