How to format numbers similar to Stack Overflow reputation format

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

e.g.

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

Solution 1:

Another approach that produces exactly the desired output:

function getRepString (rep) {
  rep = rep+''; // coerce to string
  if (rep < 1000) {
    return rep; // return the same number
  }
  if (rep < 10000) { // place a comma between
    return rep.charAt(0) + ',' + rep.substring(1);
  }
  // divide and format
  return (rep/1000).toFixed(rep % 1000 != 0)+'k';
}

Check the output results here.

Solution 2:

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'

Solution 3:

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');
}

Solution 4:

Here is CMS's version in PHP (in case someone needed it, like I did):

function getRepString($rep) {
    $rep = intval($rep);
    if ($rep < 1000) {
        return (string)$rep;
    }
    if ($rep < 10000) {
        return number_format($rep);
    }
    return number_format(($rep / 1000), ($rep % 1000 != 0)) . 'k';
}

// TEST
var_dump(getRepString(999));
var_dump(getRepString(1000));
var_dump(getRepString(9999));
var_dump(getRepString(10000));
var_dump(getRepString(10100));

Output:

string(3) "999"
string(5) "1,000"
string(5) "9,999"
string(3) "10k"
string(5) "10.1k"