选择数量最多比数组变量较小 [英] Selecting biggest number smaller than a variable in array

问题描述

我有一个JavaScript数组，像这样一个变量;

I have a JavaScript array and a variable like so;

var a = [0, 1200, 3260, 9430, 13220],
    b = 4500;

什么是选择这仍然小于或等于变量？

What would be the smartest way to select the largest value in the array that's still smaller than or equal to the variable?

在这个例子中，我需要选择 3260 。

In this example, I'd need to select 3260.

我可以做这样的事情;

I could do something like this;

$.each(a, function(i){
    if(a[i] <= b && a[i+1] > b){
        var c = a[i];
        return false;
    }
});

但我想，如果选择的数组值是最后一个，可能无法正常工作。更何况，对我来说，它看起来像很多code的东西很简单。

But I'm thinking that might not work if the selected array value is the last one. Not to mention, to me it looks like a lot of code for something rather simple.

有没有达到我后的一个聪明/更简洁的方式？

Is there a smarter/less verbose way of achieving what I'm after?

的（是的，我知道我不应该用一个jQuery环路这一点，但打字时的例子我很懒）的

推荐答案

您可以到它是通过阵列过滤的组合和应用（）的另一种方式，我认为这是一个非常可读的方式。
呼叫筛选（）只返回元件在一数组，它不满足predicate功能，然后应用（）与每个元素作为参数调用Math.max

Another way you could to it is through a combination of array filtering and apply(), which I think is a very readable approach. The call to filter() just returns an array of elements in a which don't satisfy the predicate function and then apply() calls Math.max with each element as an argument.

var a = [1, 2, 3, 4, 5];
var b = 4;
var result = Math.max.apply(Math, a.filter(function(x){return x <= b}));

结果将等于4。

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