number formatting - PHP number_format not working properly -

i have variable:

$out .= $indent . sprintf("{$total_space}%-{$column_total}s{$space}%{$price_width}s$newline", ___('tax'), am_currency::render($this->{$prefix . '_tax'}, $this->currency)); 

which time being equals 4000. need formatted this: 4,000 changed code below:

$out .= $indent . sprintf("{$total_space}%-{$column_total}s{$space}%{$price_width}s$newline", ___('tax'), am_currency::render(number_format($this->{$prefix . '_tax'}), $this->currency)); 

however, dont know why 4 instead. happened other zeros? tried different values such 1214.92 example , in cases output leaves out last 3 digits.

this render function:

static function render($value, $currency = null, $locale = null)     {         return (string)self::create($value, $currency, $locale);     }    public function __tostring()     {         $format = array_key_exists($this->currency, $this->formats) ?              $this->formats[$this->currency] :             '%.2f %s';         return sprintf($format, $this->value, $this->currency);     } 

i tried changing code above this:

        return sprintf($format, number_format($this->value), $this->currency); 

but didnt work either. can please tell me whats wrong? blowing mind!

thank you.

your sprintf format overriding number_format function...it doesn't make sense use both @ same time (at least not same number within string). if use number_format you'll see formats correctly.

i'd recommend using money_format function instead, e.g.:

//money format setlocale(lc_monetary, 'en_us'); ... return money_format('%.2n', $this->value); 

http://www.php.net/manual/en/function.money-format.php