How to format numbers similar to Stack Overflow reputation format

Question

I want to convert a number into a string representation with a format similar to Stack Overflow reputation display.

e.g.

• 999 == \'999\'
• 1000 =

Answer 1

UPDATE: CMS got the check and provides a superior answer. Send any more votes his way.

// formats a number similar to the way stack exchange sites 
// format reputation. e.g.
// for numbers< 10000 the output is '9,999'
// for numbers > 10000 the output is '10k' with one decimal place when needed
function getRepString(rep)
{
    var repString;

    if (rep < 1000)
    {
        repString = rep;
    }
    else if (rep < 10000)
    {
        // removed my rube goldberg contraption and lifted
        // CMS version of this segment
        repString = rep.charAt(0) + ',' + rep.substring(1);
    }
    else
    {
        repString = (Math.round((rep / 1000) * 10) / 10) + "k"
    }

    return repString.toString();
}

Output:

• getRepString(999) == '999'
• getRepString(1000) == '1,000'
• getRepString(9999) == '9,999'
• getRepString(10000) == '10k'
• getRepString(10100) == '10.1k'

Answer 2

Here is a function in PHP which is part of iZend - http://www.izend.org/en/manual/library/countformat:

function count_format($n, $point='.', $sep=',') {
    if ($n < 0) {
        return 0;
    }

    if ($n < 10000) {
        return number_format($n, 0, $point, $sep);
    }

    $d = $n < 1000000 ? 1000 : 1000000;

    $f = round($n / $d, 1);

    return number_format($f, $f - intval($f) ? 1 : 0, $point, $sep) . ($d == 1000 ? 'k' : 'M');
}