可以用百分比而不是静态值来完成

Question

Alright guys, Basically i've got some code which is working from an if statement, I'm wondering if it's possible to recode it to work from a percentage, here's the current code

@sort($prices_array);
if ($prices_array[1] > 10000 AND $prices_array[1] < 50000) {
    $sell_at = $prices_array[1] - 250;
} elseif ($prices_array[1] > 50000 AND $prices_array[1] < 100000) {
    $sell_at = $prices_array[1] - 500;
} else {
    $sell_at = $prices_array[1] - 100;
}
$buy_at = $prices_array[1] - 1000;

if ($prices_array[1] >= 10000) {
    $buy_at = $buy_at - 1000;
    if ($prices_array[1] >= 20000) {
        $buy_at = $buy_at - 1000;
        if ($prices_array[1] >= 30000) {
            $buy_at = $buy_at - 1000;
        }
        if ($prices_array[1] >= 40000) {
            $buy_at = $buy_at - 1000;
        }
        if ($prices_array[1] >= 50000) {
            $buy_at = $buy_at - 750;
        }
        if ($prices_array[1] >= 60000) {
            $buy_at = $buy_at - 500;
        }
        if ($prices_array[1] >= 70000) {
            $buy_at = $buy_at - 500;
        }
    }
}

I know the code is quite horribly done, but would it be possible to base the $buy_at from an certain percentage for example such as 5% lower than the sell_at but rounded to the correct decrements from the if statement

Answer 1

First of all, I think a switch would be nicer form here. Secondly, you can use this function to set up rounding to whatever increments you want:

function roundUpTo($number, $increments) { 
    $increments = 1 / $increments; 
    return (ceil($number * $increments) / $increments); 
}

To find a percentage of a value, just multiply the value by the percentage divided by 100.