Javascript数组和对象比较答案

【问题标题】：Javascript array and object comparisonJavascript数组和对象比较
【发布时间】：2018-08-06 11:43:06
【问题描述】：

我正在尝试存储一年的最高和最低温度。

所以我有一个数组和一个像这样的对象。

var Months =['January','February','March','April','May','June','July','August','September','October','November','December'];  

result[0] = {January: 26.2, February: 25.9, March: 25.7, April: 23.4, May: 19.3, June: 15.9, July: 15.4, August: 16, September: 21.3, October: 24.8, November: 26.6, December: 26.6,Type: "Min"}

result[1] = {January: 36.3, February: 35.9, March: 36, April: 36.7, May: 34.2, June: 31.4, July: 32, August: 34, September: 37.8, October: 39.5, November: 39.8, December: 37.8,Type: "Max"}.

这是我拥有的数据，现在我想要两个以正确顺序存储数据的不同数组。 (1-12月)

例如：

var min = [26.2,25.9,25.7,23.4,19.3,15.9,15.4,16,21.3,24.8,26.6,26.6]
var max = [36.3,35.9,36,36.7,34.2,31.4,32,34,37.8,39.5,39.8,37.8]

如何从对象中提取该数据并确保顺序与“月份”相同？我还需要在我的新数组中删除 Min/Max 的“类型”。

【问题讨论】：

问题是什么？迭代几个月并使用它们从对象中提取值...

标签： javascript arrays loops object

【解决方案1】：

您可以简单地使用 .map() method 从您的 result 对象映射相关月份值，并将它们分配给您的 min 和 max 变量。

这应该是你的代码：

var [min, max] = result.map(r => Months.map(m => {
  return r[m]
}));

演示：

var Months = ['January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December'];

var result = [];


result[0] = {January: 26.2, February: 25.9, March: 25.7, April: 23.4, May: 19.3, June: 15.9, July: 15.4, August: 16, September: 21.3, October: 24.8, November: 26.6, December: 26.6,Type: "Min"};

result[1] = {January: 36.3, February: 35.9, March: 36, April: 36.7, May: 34.2, June: 31.4, July: 32, August: 34, September: 37.8, October: 39.5, November: 39.8, December: 37.8,Type: "Max"};

var [min, max] = result.map(r => Months.map(m => {
  return r[m]
}));

console.log(min);
console.log(max);

【讨论】：

【解决方案2】：

您不需要任何循环。只需使用Object.values() 和pop() 即可从数组中删除最后一个元素，即Type 值。

var Months  = ['January','February','March','April','May','June','July','August','September','October','November','December'];  

var result = [{January: 26.2, February: 25.9, March: 25.7, April: 23.4, May: 19.3, June: 15.9, July: 15.4, August: 16, September: 21.3, October: 24.8, November: 26.6, December: 26.6,Type: "Min"},
 {January: 36.3, February: 35.9, March: 36, April: 36.7, May: 34.2, June: 31.4, July: 32, August: 34, September: 37.8, October: 39.5, November: 39.8, December: 37.8,Type: "Max"}];
 
 var min = Object.values(result[0]);
 min.pop();
 var max = Object.values(result[1]);
 max.pop();
 console.log(min);
 console.log(max);

【讨论】：

【解决方案3】：

您可以使用months 数组的有序元素顺序访问每个result 对象的相应月份键。由于您的月份数组不包含 Type 元素，因此该键将被忽略。

var Months =['January','February','March','April','May','June','July','August','September','October','November','December'];
var result = []
result[0] = {January: 26.2, February: 25.9, March: 25.7, April: 23.4, May: 19.3, June: 15.9, July: 15.4, August: 16, September: 21.3, October: 24.8, November: 26.6, December: 26.6,Type: "Min"}
result[1] = {January: 36.3, February: 35.9, March: 36, April: 36.7, May: 34.2, June: 31.4, July: 32, August: 34, September: 37.8, October: 39.5, November: 39.8, December: 37.8,Type: "Max"}

var min = []
var max = []

for (let month of Months) {
  min.push(result[0][month])
  max.push(result[1][month])
}

console.log(min, max)

【讨论】：