RegEx validation of decimal numbers with comma or dot

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

6 Answers

Try this regex:

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

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

Try This,

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

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> 

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

1. (\d+) : one or more digits
2. (,\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

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 

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