How to convert string to array of substrings based on the length of substring in java?

Question

I want to convert a string to an array of substrings based on the length of the substrings. is there any solution without using a loop? for example:

"this is a test" -> ["thi","s i","s a"," te","st"]

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Update:

more solutions here: Splitting a string at every n-th character

Answer 1

Look at Bart Kiers' example :

System.out.println(java.util.Arrays.toString("this is a test".split("(?<=\\\\G...)")));

The number of periods '.' indicates how many characters each sub string will be.

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EDIT

As Mick Mnemonic pointed out, you can also use Kevin Bourrillion's example :

Java does not provide very full-featured splitting utilities, so the Guava libraries do:

Iterable<String> pieces = Splitter.fixedLength(3).split(string);

Check out the Javadoc for Splitter ; it's very powerful.

If you do not want to use regular expressions, and do not wish to rely on a third party library, you can use this method instead, which takes between 89920 and 100113 nanoseconds in a 2.80 GHz CPU (less than a millisecond):

   /**
     * Divides the given string into substrings each consisting of the provided
     * length(s).
     * 
     * @param string
     *            the string to split.
     * @param defaultLength
     *            the default length used for any extra substrings. If set to
     *            <code>0</code>, the last substring will start at the sum of
     *            <code>lengths</code> and end at the end of <code>string</code>.
     * @param lengths
     *            the lengths of each substring in order. If any substring is not
     *            provided a length, it will use <code>defaultLength</code>.
     * @return the array of strings computed by splitting this string into the given
     *         substring lengths.
     */
    public static String[] divideString(String string, int defaultLength, int... lengths) {
        java.util.ArrayList<String> parts = new java.util.ArrayList<String>();

        if (lengths.length == 0) {
            parts.add(string.substring(0, defaultLength));
            string = string.substring(defaultLength);
            while (string.length() > 0) {
                if (string.length() < defaultLength) {
                    parts.add(string);
                    break;
                }
                parts.add(string.substring(0, defaultLength));
                string = string.substring(defaultLength);
            }
        } else {
            for (int i = 0, temp; i < lengths.length; i++) {
                temp = lengths[i];
                if (string.length() < temp) {
                    parts.add(string);
                    break;
                }
                parts.add(string.substring(0, temp));
                string = string.substring(temp);
            }
            while (string.length() > 0) {
                if (string.length() < defaultLength || defaultLength <= 0) {
                    parts.add(string);
                    break;
                }
                parts.add(string.substring(0, defaultLength));
                string = string.substring(defaultLength);
            }
        }

        return parts.toArray(new String[parts.size()]);
    }