How do I add leading zeros to a number?

Date: 2010-09-16. Category: java.lang examples. Hits: 95K time(s).

This example shows you how to use the String.format() method to add zero padding to a number. If you just want to print out the result you can use System.out.format(). This method is available since Java 1.5, so If you use a previous version you can use the NumberFormat class, see: How do I format a number with leading zeros?.

package org.kodejava.example.lang;

public class LeadingZerosExample {
    public static void main(String[] args) {
        int number = 1500;
        
        //
        // String format below will add leading zeros (the %0 syntax) 
        // to the number above. The length of the formatted string will 
        // be 7 characters.
        //
        String formatted = String.format("%07d", number);
        
        System.out.println("Number with leading zeros: " + formatted);
    }
}

For more information about the format syntax you can find it here.

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