regex number

const pattern = /^-?\d+(\.\d+)?$/;

// Test a string
console.log(pattern.test("42")); // true
console.log(pattern.test("3.14.15")); // false

// Match and extract
const result = "42".match(pattern);

import re

pattern = r"^-?\d+(\.\d+)?$"

# Test a string
if re.fullmatch(pattern, "42"):
    print("Valid")

# Find all matches in text
matches = re.findall(pattern, text)

import java.util.regex.*;

String pattern = "^-?\\d+(\\.\\d+)?$";
Pattern p = Pattern.compile(pattern);

Matcher m = p.matcher("42");
boolean isValid = m.matches(); // true

// Find occurrences
Matcher finder = p.matcher(inputText);
while (finder.find()) {
    System.out.println(finder.group());
}