PHP保留两位小数的数字该如何输出

$aaa = 15.0393;
var_dump(round($aaa, 2));
$bbb = 16.1;
var_dump(round($bbb, 2));
$ccc = 13;
var_dump(round($ccc, 2));
/**
运行：
double(15.04)
double(16.1)
double(13)
 */

$aaa = 15.0393;
var_dump(number_format($aaa, 2, '.', ''));

$bbb = 16.1;
var_dump(number_format($bbb, 2, '.', ''));

$ccc = 13;
var_dump(number_format($ccc, 2, '.', ''));

/**
运行：
string(5) "15.04"
string(5) "16.10"
string(5) "13.00"
 */

$aaa = 15.0393;
var_dump(sprintf('%.2f', $aaa));

$bbb = 16.1;
var_dump(sprintf('%.2f', $bbb));

$ccc = 13;
var_dump(sprintf('%.2f', $ccc));

/**
运行：
string(5) "15.04"
string(5) "16.10"
string(5) "13.00"
 */