Java Regex
This regex pattern can be used to find if the given string is a number or not.
^[-+]?\d*\.?\d+$
package com.logicbig.example;import java.util.regex.Pattern;public class NumberRegex { private static final Pattern PATTERN = Pattern.compile("^[-+]?\\d*\\.?\\d+$"); public static void main (String[] args) { check("3.43"); check("3.4.3"); check(".4"); check("..4"); check("4."); check("4"); check("-4"); check("-+4"); check("1,222.3"); } public static boolean isNumber (String str) { return PATTERN.matcher(str) .matches(); } private static void check (String s) { System.out.printf("%s %s%n", s, isNumber(s)); }}
3.43 true3.4.3 false.4 true..4 false4. false4 true-4 true-+4 false1,222.3 false