Making a String containing the same character multiple times

Question

How can I initialize a String with dynamic length in Java?

For example, I want to have a String consisting of n characters a, where n is a variable. Can I do that?

Answer 1

You can use StringBuilder and define a method called e.g. getString.

public static String getString(char ch, int n){ 
        StringBuilder sb = new StringBuilder(n);
        for (int i=0; i<n; i++){
           sb.append(ch);
        }
        String s = sb.toString();
        return s;
}

Now you can make some calls to this method.

String sA1 = getString('a', 10);
String sA2 = getString('a', 20);
String sB = getString('b', 30);
String sC = getString('c', 5);  

Answer 2

You can use StringBuilder

StringBuilder sb = new StringBuilder();
String myChar = "a";
int n = 10;
for(int i=0; i<n;i++){
   sb.append(myChar);
}

String myResult = sb.toString();

Answer 3

Arrays have a fixed length in Java. If you want the size to be dynamic, you need to use a List object

List<String> stringList = new ArrayList<String>();

Have a look at the ArrayList documentation.

And if you need array then

String[] stringArray = stringList .toArray(new String[stringList .size()]);

Answer 4

String is immutable. When you are initializing a string it is once. you cant change its size time to time. the size should n`t be dynamic.

Use other option like StringBuilder to do this

Answer 5

StringBuilder strB = new StringBuilder();
for(int i = 0; i < size; i++)
{
  strB.append("a");
}

String str = strB.toString();

Answer 6

You can use List

ArrayList<String> mylist = new ArrayList<String>();
mylist.add(mystring); //this adds an element to the list.