What is the regex for decimal number?

The regex pattern for decimal number is `^-?\d+(?:\.\d+)?$`. This pattern validates optionally signed decimal number.

How do I use this regex in JavaScript?

In JavaScript, create the regex with `const regex = /^-?\d+(?:\.\d+)?$/;` and test with `regex.test(yourValue)`. It returns `true` if the value matches.

How do I use this regex in Python?

In Python, use `import re; re.match(r'^-?\d+(?:\.\d+)?$', value)`. The raw string prefix (`r`) prevents Python from interpreting backslashes as escape characters.

Is this regex case-sensitive?

By default, yes. To make it case-insensitive, add the `i` flag in JavaScript (`/^-?\d+(?:\.\d+)?$/i`) or use `re.IGNORECASE` in Python.

Regex for Decimal Number

Regex Pattern

^-?\d+(?:\.\d+)?$

Optionally signed decimal number

Quick Answer

The regex pattern for decimal number is `^-?\d+(?:\.\d+)?$`. Optionally signed decimal number. This works in JavaScript, Python, Ruby, PHP, Java, and most regex engines that support PCRE syntax.

Test Examples

Input	Result
0	✓ Matches
42	✓ Matches
-3.14	✓ Matches
1.5	✓ Matches
-100	✓ Matches
1.5.2	✗ No match
.5	✗ No match
1,5	✗ No match
abc	✗ No match

Code Examples

javascript

const regex = /^-?\d+(?:\.\d+)?$/;
const isValid = regex.test(value);

python

import re
pattern = r'^-?\d+(?:\.\d+)?$'
if re.match(pattern, value):
    print("valid")

ruby

pattern = /^-?\d+(?:\.\d+)?$/
if value =~ pattern
  puts "valid"
end

php

if (preg_match('/^-?\d+(?:\.\d+)?$/', $value)) {
    echo "valid";
}

java

String pattern = "^-?\\d+(?:\\.\\d+)?$";
boolean isValid = value.matches(pattern);

Frequently Asked Questions

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