A string composed of a character repeated x number of times

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Sathyaish - 04 Apr 2007 10:42 GMT

In Java, what function/method do we have for constructing composed of
a single character repeated x number of times.

I am looking for the .NET equivalant of this String class constructor:

public String(char c, int numTimesToRepeat);

I looked at the java.lang.String class' constructors and couldn't find
one that matched my needs.

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Andrew T. - 04 Apr 2007 10:55 GMT

>In Java, what function/method do we have for constructing composed of
>a single character repeated x number of times.

...

>I looked at the java.lang.String class' constructors and couldn't find
>one that matched my needs.

Generally when building String's in Java,
we would use StringBuffer() in a loop.
You might use a String+="a" in a loop,
but doing so is bad for memory reasons.

I have never needed a long string of all one
character, what are they good for?
(The only thing I can think of is a pseudo
section-separator in a text document, but
I would generally write the text as HTML
and use an <HR> as separator)

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Andrew Thompson
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Sathyaish - 04 Apr 2007 11:01 GMT

Thanks, Andy.

I understand the need for StringBuffer and StringBuilder classes.

The function/method/constructor I am looking is helpful in situations
where you want to format output on the stdout. If you want to display
a variable number of control characters depending on the length of a
string which you do not know, say, something input by the user.

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Sathyaish - 04 Apr 2007 11:17 GMT

Thanks, Mike. Guess I'll just put in a loop in a custom method.

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Andrew T. - 04 Apr 2007 11:57 GMT

>Thanks, Andy.

You can show your appreciation, by remembering
that my name is Andrew.

>The function/method/constructor I am looking is helpful in situations
>where you want to format output on the stdout. If you want to display
>a variable number of control characters depending on the length of a
>string which you do not know, say, something input by the user.

System.out.printf()

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Andrew Thompson
http://www.athompson.info/andrew/

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Robert Klemme - 04 Apr 2007 12:16 GMT

>> Thanks, Andy.
>
[quoted text clipped - 7 lines]
>
> System.out.printf()

+ DecimalFormat and others.

robert

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Michael Rauscher - 04 Apr 2007 10:55 GMT

> In Java, what function/method do we have for constructing composed of
> a single character repeated x number of times.
[quoted text clipped - 5 lines]
> I looked at the java.lang.String class' constructors and couldn't find
> one that matched my needs.

There was a discussion in de.comp.lang.java some time ago. The "nicest"
solution there was:

String s = new String(new char[numTimesToRepeat]).replace((char)0, c);

Bye
Michael

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Lew - 04 Apr 2007 13:16 GMT

Sathyaish wrote:

>> In Java, what function/method do we have for constructing composed of
>> a single character repeated x number of times.
[quoted text clipped - 8 lines]
> There was a discussion in de.comp.lang.java some time ago. The "nicest"
> solution there was:

> String s = new String(new char[numTimesToRepeat]).replace((char)0, c);

The replace() has a test in it for (char) 0 at each array position.

Test-free:

char [] a = new char [numTimesToRepeat];
Arrays.fill( a, c );
String s = new String( a );

Less sexy but more efficient.

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Lew

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Knute Johnson - 04 Apr 2007 17:13 GMT

> Sathyaish wrote:
>>> In Java, what function/method do we have for constructing composed of
[quoted text clipped - 21 lines]
>
> Less sexy but more efficient.

Sometimes you might want to start with a String rather than character.
I've had this in my tricks bag for a long time.

public class StringSet {
public static String set(String str, int n) {
StringBuilder sb = new StringBuilder(n);
for (int i=0; i<n; i++)
sb.append(str);
return sb.toString();
}
}

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Knute Johnson
email s/nospam/knute/

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Daniel Pitts - 04 Apr 2007 20:03 GMT

On Apr 4, 9:13 am, Knute Johnson <nos...@rabbitbrush.frazmtn.com>
wrote:

> > Sathyaish wrote:
> >>> In Java, what function/method do we have for constructing composed of
[quoted text clipped - 39 lines]
> Knute Johnson
> email s/nospam/knute/

Better yet
public static String repeatedToString(Object obj, int times) {
final String value = String.valueOf(Obj);
StringBuilder builder = new StringBuilder(times * value.size());
for (String v: Collections.nCopies(value, times) {
builder.append(v);
}
return builder.toString();
}

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impaler - 04 Apr 2007 17:28 GMT

Try StringUtils from the jakarta commons project.
http://jakarta.apache.org/commons/lang/

All you have to do is:
String myStr = StringUtils.leftPad("", 3, 'z'); //result myStr =
"zzz"

HTH

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Roedy Green - 04 Apr 2007 19:31 GMT

>In Java, what function/method do we have for constructing composed of
>a single character repeated x number of times.
[quoted text clipped - 5 lines]
>I looked at the java.lang.String class' constructors and couldn't find
>one that matched my needs.

see StringTools.rep, part of the common11 package.

See http://mindprod.com/products1.html#COMMON11

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Canadian Mind Products, Roedy Green, http://mindprod.com
Priorities: Prevent global climate destabilisation. End both wars. Prepare for oil shortages.

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A string composed of a character repeated x number of times

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