Remove Leading Zeroes from a String in Java using regular expressions

The replaceAll() method of the String class accepts two strings representing a regular expression and a replacement String and replaces the matched values with given String.

Following is the regular expression to match the leading zeros of a string −

The ^0+(?!$)";

To remove the leading zeros from a string pass this as first parameter and “” as second parameter.

Example

The following Java program reads an integer value from the user into a String and removes the leading zeroes from it using the Regular expressions.

Live Demo

import java.util.Scanner; public class LeadingZeroesRE {    public static String removeLeadingZeroes(String str) {       String strPattern = "^0+(?!$)";       str = str.replaceAll(strPattern, "");       return str;    }    public static void main(String args[]){       Scanner sc = new Scanner(System.in);       System.out.println("Enter an integer: ");       String num = sc.next();       String result = LeadingZeroesRE.removeLeadingZeroes(num);       System.out.println(result);    } }

Output

Enter an integer: 000012336000 12336000