Java generating a Blanks String

Question

is there a more efficient way to generate a String full of blanks with a customizable size like the following:

private String getBlanks (int numberOfBlanks)
    {
        String theBlanks = "";
        for (int i = 0; i < numberOfBlanks; i++)
        {
            theBlanks = theBlanks + " ";
        }
        return theBlanks;
    }

Perhaps with a StringBuilder or any other type?

EDIT: Since we have Appache Commons Lang the most convinient way of doing is through the use of String Utils - leftPad, thanks everyone for the answers!

Thanks

Efficient in what way? Coding complexity or execution time? Either way, the question is almost moot in terms of why it would need to be made more efficient. — Tejs
– Tejs, Commented May 10, 2011 at 15:07
I disagree on this one. Though it wouldn't be a horrible crime againt humanity to do it this way, it's not at all tidy to manipulate Strings this way. Amines answer below is (IMO) the way to do it. — Martijn
– Martijn, Commented May 10, 2011 at 15:10
On a side note, consider using StrBuilder (part of apache commons lang) instead of StringBuilder. it is a drop in replacement and the apache folks claim it is better (in general I take them at their word). — DwB
– DwB, Commented May 10, 2011 at 15:26

bruno conde · Accepted Answer · 2011-05-10 15:11:11Z

7

Maybe like this:

private String getBlanks(int numberOfBlanks) {
       char[] chars = new char[numberOfBlanks];
       Arrays.fill(chars, (char)32);
       return new String(chars);
}

answered May 10, 2011 at 15:11

bruno conde

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1 Comment

Anthony Accioly Over a year ago

Very clever (and some really long phrase so that I can publish it).

Jeremy · Accepted Answer · 2011-05-10 15:13:49Z

5

With Guava

String blanks = Strings.repeat(" ", numOfblanks);

edited May 10, 2011 at 15:13

answered May 10, 2011 at 15:08

Jeremy

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Comments

Anthony Accioly · Accepted Answer · 2011-05-10 15:09:52Z

4

Quick hack using StringUtils:

return StringUtils.leftPad("", numberOfBlanks, ' ');

answered May 10, 2011 at 15:09

Anthony Accioly

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2 Comments

Anthony Accioly Over a year ago

Oh, I forgot to say, you need Apache Commons Lang for this

camiloqp Over a year ago

We have Appache Commons and I find this way the most efficient :)

StKiller · Accepted Answer · 2011-05-10 15:07:49Z

2

First of all - use a StringBuilder, and then return StringBuilder.toString

answered May 10, 2011 at 15:07

StKiller

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Comments

Femi · Accepted Answer · 2011-05-10 15:09:16Z

2

You want a StringBuilder:

private String getBlanks (int numberOfBlanks)
    {
        StringBuilder theBlanks = new StringBuilder(numberOfBlanks);
        for (int i = 0; i < numberOfBlanks; i++) theBlanks.append(" ");
        return theBlanks.toString();
    }

answered May 10, 2011 at 15:09

Femi

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Martijn · Accepted Answer · 2011-05-10 15:14:16Z

2

String getBlankString(int length){
  StringBuffer sb=new StringBuffer(length);

  for(int i=0;i<length;i++){
    sb.append(" ");
  }
  return sb.toString();
}

edited May 10, 2011 at 15:14

Martijn

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answered May 10, 2011 at 15:07

VirtualTroll

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1 Comment

StKiller Over a year ago

StringBuffer is thread safe, it's necessary only in specific cases, otherwise it is only adding additional locking.

Alan Escreet · Accepted Answer · 2011-05-10 15:23:15Z

1

private String getBlanks (int numberOfBlanks) {
    StringBuilder sb = new StringBuilder();
    sb.setLength(numberOfBlanks);
    sb.replace(0, numberOfBlanks-1, " ");

    return sb.toString();
}

answered May 10, 2011 at 15:23

Alan Escreet

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