如何确定我的号码最接近哪个数组索引? [英] How can I determine which array index my number is closest to?

问题描述

我有一个如下所示的数组和变量:

I have an array and var that look like this:

var paymentMilestones = [0, 30, 60, 90];
var daysOverdue = 33;

在 JavaScript 中，如何以编程方式确定 daysOverdue 变量最接近哪个 paymentMilestones 索引?我需要返回那个值，所以在这种情况下，函数应该返回 30.

In JavaScript, how can I programmatically determine which of the paymentMilestones indexes the daysOverdue var is closest to? I need that value returned, so in this case the function should return 30.

推荐答案

快速回答(如果有平局，它将带回两者 - 假设数组已预先排序):

A quick answer (if there is a tie it will bring back both - assuming the array is pre-sorted):

var paymentMilestones = [0, 30, 60, 90];
var daysOverdue = 33;

function findClose(array,elem){
    var minDelta = null;
    var minIndex = null;
    for (var i = 0 ; i<array.length; i++){
        var delta = Math.abs(array[i]-elem);
        if (minDelta == null || delta < minDelta){
            minDelta = delta;
            minIndex = i;
        }
        else if (delta == minDelta) {
            return [array[minIndex],array[i]];
        }
        // unchecked: stop if delta starts becoming bigger again
        else { 
            return [array[i-1]];
        }


    }
    return array[minIndex];
}
var closest = findClose(paymentMilestones,daysOverdue);

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