[removed] rounding a float UP to nearest .25 (or whatever…)

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广开言路
广开言路 2021-01-21 03:39

All answers I can find are rounding to nearest, not up to the value... for example

1.0005 => 1.25  (not 1.00)
1.9   => 2.00
2.10 => 2.25
2.59 => 2.75         


        
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  • 2021-01-21 04:15

    Multiply the number by 4, use Math.ceil on the result and then divide that number by 4.

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  • 2021-01-21 04:15

    Just multilpy by 4 and take the ceiled value with 4 times.

    var values = [1.0005, 1.9, 2.10, 2.59],
        round = values.map(function (a) { return Math.ceil(a * 4) / 4; });
    
    document.write('<pre>' + JSON.stringify(round, 0, 4) + '</pre>');

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  • 2021-01-21 04:23

    Divide the number by 0.25 (or whatever fraction you want to round nearest to).

    Round up to nearest whole number.

    Multiply result by 0.25.

    Math.ceil(1.0005 / 0.25) * 0.25
    // 1.25
    
    Math.ceil(1.9 / 0.25) * 0.25
    // 2
    
    // etc.
    

    function toNearest(num, frac) {
      return Math.ceil(num / frac) * frac;
    }
    
    var o = document.getElementById("output");
    
    o.innerHTML += "1.0005 => " + toNearest(1.0005, 0.25) + "<br>";
    o.innerHTML += "1.9 => " + toNearest(1.9, 0.25) + "<br>";
    o.innerHTML += "2.10 => " + toNearest(2.10, 0.25) + "<br>";
    o.innerHTML += "2.59 => " + toNearest(2.59, 0.25);
    <div id="output"></div>

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  • 2021-01-21 04:23

    Other divide and multiply will not work for some values such as 1.59 You can try customRound function

    function customRound(x) {
        var rest = x - Math.floor(x)
    
        if (rest >= 0.875) {
            return Math.floor(x) + 1
        } else if (rest >= 0.625) {
            return Math.floor(x) + 0.75
        } else if (rest >= 0.375) {
            return Math.floor(x) + 0.50
        }  else if (rest >= 0.125){
            return Math.floor(x) + 0.25
        } else {
            return Math.floor(x)
        }
    }
    
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