Converting values to unit prefixes in JSP page

Question

How can I convert values to to other units in JSP page. For example if I get value 1001 and I want to only display 1K, or when I get 1 000 001 I would like to display 1M and

Answer 1

This problem can (and should in my opinion) be solved without loops.

Here's how:

public static String withSuffix(long count) {
    if (count < 1000) return "" + count;
    int exp = (int) (Math.log(count) / Math.log(1000));
    return String.format("%.1f %c",
                         count / Math.pow(1000, exp),
                         "kMGTPE".charAt(exp-1));
}

---

Test code:

for (long num : new long[] { 0, 27, 999, 1000, 110592,
                             28991029248L, 9223372036854775807L })
   System.out.printf("%20d: %8s%n", num, withSuffix(num));

Output:

                   0:        0
                  27:       27
                 999:      999
                1000:    1.0 k
              110592:  110.6 k
         28991029248:   29.0 G
 9223372036854775807:    9.2 E

Related question (and original source):

• How to convert byte size into human readable format in java?