How to create String of length consisting of same character repeated multiple times?

Question

If i want a String s which would consist of n instances of character A, can this be done cleaner in Java other then

public static String stringOfSize(int size, char ch) {
    StringBuilder s = new StringBuilder();
    while (size-- > 0) {
        s.append(ch);
    }
    return s.toString();
}

Can we do better? Just wondering.

It would be cleaner if you didn't change the parameter variable, but otherwise it looks good to me. — Keppil, May 28 '13 at 19:52

score 18 · Accepted Answer · answered May 28 '13 at 19:54

18

Nothing wrong with this code at all... But maybe you can use Arrays.fill():

public static String stringOfSize(int size, char ch)
{
    final char[] array = new char[size];
    Arrays.fill(array, ch);
    return new String(array);
}

answered May 28 '13 at 19:54

fge

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I think that this option is the best. To increase speed (but consume more memory) we can also add caching to this solution. Store results in `Map> cache` and then just get right string without generation. – Grzegorz Gajos May 28 '13 at 20:06

Justin Bicknell · Answer 2 · 2013-05-28T20:06:36.153

7

You could do the following:

return StringUtils.repeat(ch, size);

Note: StringUtils is not built-in to the JDK - see http://commons.apache.org/proper/commons-lang/

edited May 28 '13 at 20:06

answered May 28 '13 at 19:54

Justin Bicknell

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There is no builtin `StringUtils` in the JDK. – fge May 28 '13 at 19:55
Or just `StringUtils#repeat()` if `StringUtils` is available. – Keppil May 28 '13 at 19:55
@fge - you are right, added a note – Justin Bicknell May 28 '13 at 19:58
@Keppil - thanks, that's much nicer – Justin Bicknell May 28 '13 at 20:01

How to create String of length consisting of same character repeated multiple times?

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