Add Leading Zeroes to Number in Java

Add leading zeroes to number in Java?

String.format (https://docs.oracle.com/javase/1.5.0/docs/api/java/util/Formatter.html#syntax)

In your case it will be:

String formatted = String.format("%03d", num);

• 0 - to pad with zeros
• 3 - to set width to 3

Add leading Zeros to converted Integer Java

An integer can't have leading zeros.

As leading zeros add no mathematical significance for an integer, they will not be stored as such. Leading zeros most likely only add to the readability for the human viewing / processing the value. For that usage a string can be used in the way you already found yourself.

How can I pad an integer with zeros on the left?

Use java.lang.String.format(String,Object...) like this:

String.format("%05d", yournumber);

for zero-padding with a length of 5. For hexadecimal output replace the d with an x as in "%05x".

The full formatting options are documented as part of java.util.Formatter.

How to add leading zeros to an int?

You will need to preserve the value as a String. You should do this anyway with something like an ISBN number since its value is not its magnitude but its string representation.

Why not just use " String num = sc.next(); " ?

How to format a Java string with leading zero?

In case you have to do it without the help of a library:

("00000000" + "Apple").substring("Apple".length())

(Works, as long as your String isn't longer than 8 chars.)

How do I pad a negative integer with leading zeroes?

Unfortunately, there is no Java format available that does this: They format on total string width, not on number of zeroes. The easiest way is to vary the length of the padding depending on whether the argument is negative:

def digitFormatter(long: Long, numDigits: Int): String = {
  val padlength = if (long >= 0) numDigits else numDigits + 1
  String.format(s"%0${padlength}d", long)
}

How to add leading zeros in a string of numbers to complete it to become a required 9 digit number

Use String.format (http://java.sun.com/j2se/1.5.0/docs/api/java/util/Formatter.html#syntax)

Your case would use: String.format("%09d", number)

Java add leading zeros to a number

When areaCode is 0, you forget to call format! Other than that, it looks fine. The leading "#" are not necessary, but won't cause any problems for valid inputs.

I just tried it out real quick to check and it worked fine for me.

public static String formatTest(int areaCode, int exchangeCode, int number) {
    DecimalFormat nf3 = new DecimalFormat("#000");
    DecimalFormat nf4 = new DecimalFormat("#0000");
    if( areaCode != 0)
        return nf3.format(areaCode) + "-" + nf3.format(exchangeCode) + "-" + nf4.format(number);
    else
        return nf3.format(exchangeCode) + "-" + nf4.format(number);
}


public static void main(String[] args) {
    System.out.println(formatTest(12, 90, 8));
    System.out.println(formatTest(1, 953, 1932));
}

Output:

012-090-0008
001-953-1932

---

Related Topics