如何计算相对百分比（将分数应用于新范围）？

Question

我是一名前端和后端开发人员，在处理简单的游戏开发和动画时遇到过几次这样的挑战。我希望我有一个函数来解决这个问题，所以我希望你数学 guys/gals 可以帮助我解决伪代码，然后我可以 post 一个我们可以运行通过的函数浏览器进行测试。

这个挑战对我来说有点难解释，所以请原谅我，我会像谜语一样给出它：

You're trying to find your test score as a percent. You know that for a normal percent, expressed as a decimal from 0.00 - 1.00, you'd do something like actual_test_score / max_test_score.

However, you're not looking for any old percent. You'd like to express your percent as a decimal within a specified range of decimal numbers. For example, you'd like (given an actual_test_score and a max_test_score) to get your test score as a percent from 0.50 - 1.00.

How can you calculate actual_test_score / max_test_score expressed as a percentage between a range of 0.50 - 1.00, instead of your typical range that is 0.00 - 1.00.

我花了一些时间来解释这一点（这可能不是最好的解释），因为这不是我必须经常解释的事情，但我运行时不时地也会这样做。

Answer 1

如果我没看错，你希望 0 表示为 0.5 吗？

在那种情况下，您需要将您的数字乘以分数范围； highest_score - lowest_score 在您的情况下似乎是 1 - 0.5。然后将 lowest_score 添加到您的结果中。

这里是粗函数形式的例子；

function relative_percentage (score, max_score, min_score) {
    // score should be a value from 0 to 1.
    return score * (max_score - min_score) + min_score;
}

Answer 2

这是从[0,1]到[newMin,newMax]的线性范围映射，这是从[oldMin,oldMax]到[newMin,newMax]的一般线性范围映射的特例：

function linearRemap(value, oldMin, oldMax, newMin, newMax) {
    var newScale = newMax - newMin;
    var valueAsPct = (val - oldMin) / (oldMax - oldMin);
    var scaledValue = valueAsPct * newScale;
    var shiftedAndScaledValue = scaledValue + newMin;
    return shiftedAndScaledValue;
}

因此这里的有限情况允许您跳过百分比计算行：

function linearRemapPct(valueAsPct, newMin, newMax) {
    var newScale = newMax - newMin;
    var scaledValue = valueAsPct * newScale;
    var shiftedAndScaledValue = scaledValue + newMin;
    return shiftedAndScaledValue;
}

或者只是

function linearRemapPct(valueAsPct, newMin, newMax) {
    return (valueAsPct * (newMax - newMin) + newMin);
}

如果你想要一些更小心的精度损失：

function linearRemapPct(valueAsPct, newMin, newMax) {
    return (valueAsPct * newMax) + (1 - valueAsPct) * newMin;
}

如何计算相对百分比（将分数应用于新范围）？

How to calculate relative percentage (apply score to a new range)?

javascript

math

pseudocode