使用PHP将舍入数字逼近0.2

Question

I'm creating this rating system using 5-edged stars. And I want the heading to include the average rating. So I've created stars showing 1/5ths. Using "1.2" I'll get a full star and one point on the next star and so on...

But I haven't found a good way to round up to the closest .2... I figured I could multiply by 10, then round of, and then run a switch to round 1 up to 2, 3 up to 4 and so on. But that seems tedious and unnecessary...

Answer 1

round(3.78 * 5) / 5 = 3.8

Answer 2

A flexible solution

function roundToNearestFraction( $number, $fractionAsDecimal )
{
     $factor = 1 / $fractionAsDecimal;
     return round( $number * $factor ) / $factor;
}

// Round to nearest fifth
echo roundToNearestFraction( 3.78, 1/5 );

// Round to nearest third
echo roundToNearestFraction( 3.78, 1/3 );

Answer 3

function round2($original) {
    $times5 = $original * 5;
    return round($times5) / 5;
}

Answer 4

So your total is 25, would it be possible to not use floats and use 1->25/25? That way there is less calculations needed... (if any at all)

Answer 5

Why is everyone giving solutions that require a deeper inspection or conversion? Want 0.2? Then:

round($n / 0.2) * 0.2; // $n = 3.78 / 0.2 = 18.9 (=) 19 * 0.2 = 3.8 //

Want 5? Then:

round($n / 5) * 5; // $n = 17 / 5 = 3.4 (=) 3 * 5 = 15 //

It's as simple as that.