Java - Create a new String instance with specified length and filled with specific character. Best solution?

user_214597 0
Viewed 193361

I did check the other questions; this question has its focus on solving this particular question the most efficient way.

Sometimes you want to create a new string with a specified length, and with a default character filling the entire string.

ie, it would be cool if you could do new String(10, '*') and create a new String from there, with a length of 10 characters all having a *.

Because such a constructor does not exist, and you cannot extend from String, you have either to create a wrapper class or a method to do this for you.

At this moment I am using this:

protected String getStringWithLengthAndFilledWithCharacter(int length, char charToFill) {
    char[] array = new char[length];
    int pos = 0;
    while (pos < length) {
        array[pos] = charToFill;
        pos++;
    }
    return new String(array);
}

It still lacks any checking (ie, when length is 0 it will not work). I am constructing the array first because I believe it is faster than using string concatination or using a StringBuffer to do so.

Anyone else has a better sollution?

java string
16 Answers

In Java 11, you have repeat:

String s = " ";
s = s.repeat(1);

(Although at the time of writing still subject to change)

user_9935470

using Dollar is simple:

String filled = $("=").repeat(10).toString(); // produces "=========="
user_892660
Related