js - 如何根据对象数组中另一个键的值更改一个键的值 [英] js - How to change one key's value based on another key's value in array of objects

问题描述

我有一个像这样的对象数组：

I have an array of objects like this:

var chartData = [{count: 0, idTag: "24"}
                 {count: 0, idTag: "25"}
                 {count: 0, idTag: "26"}]

我的代码做了一些工作并生成了一个数字（ totalValue ）。如果 totalValue 与 idTag 匹配，则其 count 会增加一个：

My code does some work and generates a number (totalValue). If totalValue matches the idTag, its count gets increased by one:

for (i=0; i<timesFlipped; i++) {
    totalValue = runTrial();
    for (j=0; j<chartData.length; j++) {
        if (chartData[j].idTag === totalValue) {
            chartData[j].count += 1;
            break;
        }
    }
}

这是一个简单的例子，但 chartData 可以容纳几十个对象，而 timesFlipped 可以是数十万次迭代。

This is a simple example, but chartData could hold a few dozen objects, and timesFlipped can be hundreds of thousands of iterations.

这是根据匹配 idTag 计数值的最佳方法>价值？有没有办法只使用正确的 idTag 值找到数组的索引而不迭代整个对象数组？

Is this the best way to change the count value based on matching the idTag value? Is there a way to just find the index of the array with the correct idTag value without iterating over the whole array of objects?

如果您需要更多上下文，请点击此处我正在处理的页面： http：// blue .butler.edu / ~azazman / coupling /

Here's the page I'm working on if you want more context: http://blue.butler.edu/~aazman/coupling/

更新：

感谢您的所有建议。我根据我所看到的情况形成了自己的解决方案。关于该项目的更多背景使我得到了我的解决方案：

Thanks for all the suggestions. I kinda formed my own solution based on what I saw. A bit more background about the project which led me to my solution:

• chartData 和min idTag值是根据用户输入点击提交时计算的。


• 一次 min 和 length （因此已知max idTag），迭代初始化 chartData ：

• The length of chartData and the min idTag value are calculated based on user inputs when they click submit
• Once min and length are calculated (thus the max idTag is known), chartData is iteratively initialized:

var min = 23-5 * numNickel-numPenny; // numNickel& numPenny是用户输入

var length = 5 *（2 * numNickel + 1）+ 2 * numPenny;

var tempTag = min;

for（j = 0; j< length; j ++）{

chartData [j] = {count：0，idTag = tempTag};

tempTag ++;

}

• 由于特定于游戏规则的原因，idTag值（无论多少）都以 idTag：25 为对称中心（例如idTags = {24 ，25,26}或idTags = {20,21,22,23,24,25,26,27,28,29,30}。无论的长度为chartData ，长度将始终为奇数且 idTag：25 将始终为 [（chartData.length-1）/ 2] 'th index。

• For reasons particular to the rules of the game, the idTag values (however many there are) are symmetrically centered around idTag:25 (e.g. idTags = {24, 25, 26} or idTags = {20,21,22,23,24,25,26,27,28,29,30}. No matter the length of chartData, the length will always be odd and idTag:25 will always be the [(chartData.length-1)/2]'th index.

因此，如果idTags为 chartData {20,21,22,23,24,25,26,27,28,29,30} 以及 runTrial（）给出 totalValue = 22 ，然后 idTag：22 将始终位于索引（totalValue - min）。

Thus, if the idTags for chartData are {20,21,22,23,24,25,26,27,28,29,30} and if runTrial() gives totalValue = 22, then idTag:22 will always be at index (totalValue - min).

所以我改变了chartData的初始化以及计数增加到的方式：

So I changed the initialization of chartData and the way the count gets increased to:

for (j=0; j<length; j++) {
    chartData[j] = {count: 0};  //based on what I'm doing with chartData next, I need each index to still be an object
}

for (i=0; i<timesFlipped; i++) {
    totalValue = runTrial();
    var index = totalValue - min;
    chartData[index].count++;
}

非常感谢大家的帮助：）

So thanks all for your help :)

推荐答案

如果您可以自由更改chartData的结构，为什么不将其设为哈希而不是数组呢？

If you're free to change the structure of chartData, why not just make it a hash instead of an array?

var chartData = {24: 0,
                 25: 0,
                 26: 0};

然后循环变为

for (i=0; i<timesFlipped; i++) {
    chartData[runTrial()]++;        
}

这篇关于js - 如何根据对象数组中另一个键的值更改一个键的值的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！