PHP Round功能 - 最高可达2 dp？

In PHP how would i round up the value 22.04496 so that it becomes 22.05? It seems that round(22.04496,2) = 22.04. Should it not be 22.05??

Thanks in advance

Why should it be 22.05? The third decimal is less than 5, hence when you round it to 2 decimal precision it's rounded down to 22.04

The round function of PHP can handle an additional argument, which controls how the rounding is done: http://php.net/manual/en/function.round.php

Examples from the link:

echo round(9.5, 0, PHP_ROUND_HALF_UP);   // 10
echo round(9.5, 0, PHP_ROUND_HALF_DOWN); // 9
echo round(9.5, 0, PHP_ROUND_HALF_EVEN); // 10
echo round(9.5, 0, PHP_ROUND_HALF_ODD);  // 9

you can do it using ceil and multiplying and dividing by a power of 10.

echo ceil( 1.012345 * 1000)/1000;

1.013

Do not do multiplication inside a ceil, floor or round function! You'll get floating point errors and it can be extremely unpredictable. To avoid this do:

function ceiling($value, $precision = 0) {
    $offset = 0.5;
    if ($precision !== 0)
        $offset /= pow(10, $precision);
    $final = round($value + $offset, $precision, PHP_ROUND_HALF_DOWN);
    return ($final == -0 ? 0 : $final);
}

For example ceiling(2.2200001, 2) will give 2.23.

Based on comments I've also added my floor function as this has similar problems:

function flooring($value, $precision = 0) {
    $offset = -0.5;
    if ($precision !== 0)
        $offset /= pow(10, $precision);
    $final = round($value + $offset, $precision, PHP_ROUND_HALF_UP);
    return ($final == -0 ? 0 : $final);
}

I think the best way:

echo ceil(round($value * 100)) / 100;

Example:

$value = 77.4;
echo ceil($value * 100) / 100; // 77.41 - WRONG!
echo ceil(round($value * 100)) / 100; // 77.4 - OK!