Convert integer to equivalent number of blank spaces.

Question

I was wondering what the easiest way is to convert an integer to the equivalent number of blank spaces. I need it for the spaces between nodes when printing a binary search tree. I tried this

  int position = printNode.getPosition(); 
  String formatter = "%1"+position+"s%2$s\n";
  System.out.format(formatter, "", node.element);

But I am getting almost 3 times as many spaces compared to the int value of position. I'm not really sure if I am formatting the string right either. Any suggestions would be great! If it makes it clearer, say position = 6; I want 6 blank spaces printed before my node element.

Answer 1

Why not loop over the integer and add a space on each iteration?

String spaces = "";
for (int i = 0 ; i < position ; i++) spaces += " ";

And you can use StringBuilder instead of String, if position might get very big and performance is an issue.

Answer 2

I think you meant something like:

    int n = 6;
    String s = String.format("%1$#"+n+"s", "");

---

System.out.format("[%13s]%n", "");  // prints "[             ]" (13 spaces)
System.out.format("[%1$3s]%n", ""); // prints "[   ]" (3 spaces)

Answer 3

You can create a char[] of the desired length, Arrays.fill it with spaces, and then create a String out of it (or just append to your own StringBuilder etc).

import java.util.Arrays;

int n = 6;
char[] spaces = new char[n];
Arrays.fill(spaces, ' ');
System.out.println(new String(spaces) + "!");
// prints "      !"

If you're doing this with a lot of possible values of n, instead of creating and filling new char[n] every time, you can create just one long enough string of spaces and take shorter substring as needed.

Answer 4

Straight foward solution:

int count = 20;

StringBuilder sb = new StringBuilder(count);
for (int i=0; i < count; i++){
 sb.append(" ");
}
String s = sb.toString();

StringBuilder is efficient in terms of speed.

Answer 5

This is an easy, but rubbish, way:

 int count = 20;
 String spaces = String.format("%"+count+"s", "");

or filled in

String spaces = String.format("%20s", "");