Can one initialize a Java string with a single repeated character to a specific length

Question

I'd like to create a function that has the following signature:

public String createString(int length, char ch)

It should return a string of repeating characters of the specified length.
For example if length is 5 and ch is 'p' the return value should be:

ppppp

Is there a way to do this without looping until it is the required length?
And without any externally defined constants?

It does look like a duplicate question, but the answers here are much nicer :) — Ron Tuffin, Dec 05 '13 at 15:31

score 109 · Accepted Answer · edited Oct 21 '19 at 13:50

109

char[] chars = new char[len];
Arrays.fill(chars, ch);
String s = new String(chars);

edited Oct 21 '19 at 13:50

Mike

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answered Dec 14 '09 at 11:54

Joel Shemtov

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Really simple and helpful. – Nguyen Minh Binh Jan 26 '13 at 03:43

score 40 · Answer 2 · edited Apr 04 '14 at 05:45

40

StringUtils.repeat(str, count) from apache commons-lang

edited Apr 04 '14 at 05:45

Eugene Evdokimov

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answered Dec 14 '09 at 11:55

Bozho

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Perfect! Why write three lines when you can write 1? – deGoot May 08 '15 at 00:42
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@deGoot, cause you need third-party library for that – zegoline Jul 30 '15 at 11:45
which you probably already have.. :) – Bozho Aug 02 '15 at 21:46
@Bozho not rly..... – Antoniossss Sep 13 '22 at 20:09

Mike · Answer 3 · 2020-07-09T08:18:34.607

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Here is an elegant, pure Java, one-line solution:

Java 11+:

String str = "p".repeat(5); // "ppppp"

prior Java 11:

String str = new String(new char[5]).replace("\0", "p"); // "ppppp"

edited Jul 09 '20 at 08:18

answered Jan 20 '17 at 11:26

Mike

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Seeing all the solutions, I wonder whether `String` should have a constructor like `String(int size, char filler)` or a method `fillWith(char filler)`. – U. Windl May 11 '18 at 10:34

score 8 · Answer 4 · answered Nov 21 '15 at 18:33

8

For the record, with Java8 you can do that with streams:

String p10times = IntStream.range(0, 10)
  .mapToObj(x -> "p")
  .collect(Collectors.joining());

But this seems somewhat overkill.

answered Nov 21 '15 at 18:33

T.Gounelle

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Upvoted for coolness. – Eric Keyte Jun 28 '16 at 07:27
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To avoid generating and discarding the IntStream values `String p10Times = Stream.generate(() -> "p").limit(10).collect(Collectors.joining());` – Jelaby Feb 06 '17 at 12:27

score 1 · Answer 5 · answered Jan 20 '17 at 11:52

Bit more advance and readable ,

 public static String repeat(int len, String ch) {

        String s = IntStream.generate(() -> 1).limit(len).mapToObj(x -> ch).collect(Collectors.joining());
        System.out.println("s " + s);
        return s;    
    }

Can one initialize a Java string with a single repeated character to a specific length

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