string based on int value

Question

what I am looking to do here is create a string based on the value of an int.

I know I am able to create a vale of an in based on a sting via the length() method but was wondering how to do the opposite.

for example I have an int of 30, with that int I would like to create 30 dots ina line based on that int and place it in a println

 {


     while (wordlegnth1 + wordlegnth2 < LINELENGTH)

     {

         dots++;
         wordlegnth1++;

     }

     System.out.println (word1 + dots + word2);
   }

at the moment, al the println does is prints the 2 words entered, the int value based on the 2 words entered eg stack24overflow

basically what I would like to do is change that 24 from an int into 24 dots (........................)

many thanks :)

possible duplicate of Padding Strings in Java

Stephen C
– Stephen C

2010-11-10 01:35:53 +00:00
Commented Nov 10, 2010 at 1:35 — Stephen C
– Stephen C, Commented Nov 10, 2010 at 1:35

Community · Accepted Answer · 2017-05-23 11:47:40Z

2

This is a special case of wanting to repeat a string (or a character, for that matter) some number of times.

However, there's a simple solution of just looping to output a period dots number of times and printing that directly to the screen:

System.out.print(word1);
for(int d = 0; d < dots; d++){
    System.out.print(".");
}
System.out.println(word2);

Alternatively you can form a string (using StringBuilder) first and then output it:

StringBuilder sb = new StringBuilder(dots);
for(int d = 0; d < dots; d++){
    sb.append('.');
}
System.out.println(word1 + sb + word2);

Note that the StringBuilder's capacity is initialized to dots.

edited May 23, 2017 at 11:47

CommunityBot

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answered Nov 10, 2010 at 0:25

Mark Elliot

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2 Comments

austinbv Over a year ago

That doesn't actually create a string of dots instead it just would print a bunch of them.

Mark Elliot Over a year ago

@zobgib: the OP didn't ask to create a string of periods, rather, to output the number of periods corresponding to dots, that's what this does, and all it claims to do.

austinbv · Accepted Answer · 2010-11-10 00:26:24Z

1

int x - 30;
String dots = "";
for (int i = 0; i < x; i++){
     dots += "."; 
}
System.out.println(dots);

What I am doing is taking the int value and looping that many times. The then += operator concatenates the dots variable. So for instance "." + "." = ".."

answered Nov 10, 2010 at 0:26

austinbv

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2 Comments

Stephen C Over a year ago

String concatenation in a loop is inefficient.

Ari Gesher Over a year ago

True. It creates (and then discards) a StringBuilder under the covers.

Stephen C · Accepted Answer · 2010-11-10 01:45:20Z

There are many ways to do this.

Here's a cheap and simple one, albeit not very general:

    static final String manyDots = "...........................................";
    ...
    dots = manyDots.substring(0, nosDots);  // if nosDots <= manyDots.length()

Here's a more general version:

    char[] dotChars = new char[nosDots];
    Arrays.fill(dotChars, '.');    
    dots = new String(dotChars);

... which is more or less equivalent to:

    StringBuilder sb = new StringBuilder(nosDots);
    for (int i = 0; i < nosDots; i++) {
        sb.append('.');
    }
    dots = sb.toString();

The Apache Commons StringUtils class has various methods for this kind of thing; e.g. leftPad, rightPad, center and repeat. Calling StringUtils.repeat(".", nosDots) would do exactly what you are trying to do.

Finally, the String.format() method and the Formatter classes do this kind of thing, in a higher level way.

Tag · Accepted Answer · 2010-11-10 06:46:40Z

1

char[] letters = new char[ 30 ];
Arrays.fill(letters, '.');
String s = new String( letters );

System.out.println( s );

answered Nov 10, 2010 at 6:46

Tag

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