试图在一组对象中找到最冷和最热的城市

如何解决试图在一组对象中找到最冷和最热的城市

// function
function findColdHot(array) {
  // create an empty object
  var resultObj = {};
  // create coldest and hottest variables
  let coldest = Infinity
  let hottest = -Infinity
  // iterate over the array
  for (let i = 0; i < array.length; i++) {
    if (array[i].temp > hottest) {
      hottest = array[i].city;
    } else if (array[i].temp < coldest) {
      coldest = array[i].city;
    }
  }
  // create coldest and hottest properties
  resultObj['Coldest Place'] = coldest
  resultObj['Hottest Place'] = hottest;
  // return result object
  return resultObj;
}
// tests
var input = [
  {city: 'Helsinki',temp: 12},{city: 'Berlin',temp: 10},{city: 'oslo',temp: 4},{city: 'Nairobi',temp: 39},{city: 'Paris',temp: 6},{city: 'Istanbul',{city: 'Rome',temp: 25}
];
var actual = findColdHot(input);
var expected = {'Coldest Place': 'oslo','Hottest Place': 'Nairobi'};
console.log(actual)

我想弄清楚如何使用 for 循环并获取最冷和最热的城市。我还尝试将最冷和最热的变量更改为：

let coldest = array.[0].temp
let hottest = array[0].temp

然后开始 for 循环 i = 1 但它仍然不起作用

我得到的不是预期的输出：

{ 'Coldest Place': 'Berlin','Hottest Place': 'Helsinki' }

或

{ 'Coldest Place': 'Berlin','Hottest Place': 'Nairobi' }

任何帮助将不胜感激！

解决方法

我对现有代码进行了一些更改，现在可以使用了

// function
function findColdHot(array) {
  // create an empty object
  var resultObj = {};
  // create coldest and hottest variables
  let coldest = array[0];
  let hottest = array[0];
  // iterate over the array
  for (let i = 0; i < array.length; i++) {
    if (array[i].temp > hottest.temp) {
      hottest = array[i];
    } else if (array[i].temp < coldest.temp) {
      coldest = array[i];
    }
  }
  // create coldest and hottest properties
  resultObj['Coldest Place'] = coldest.city;
  resultObj['Hottest Place'] = hottest.city;
  // return result object
  return resultObj;
}
// tests
var input = [
  {city: 'Helsinki',temp: 12},{city: 'Berlin',temp: 10},{city: 'Oslo',temp: 4},{city: 'Nairobi',temp: 39},{city: 'Paris',temp: 6},{city: 'Istanbul',{city: 'Rome',temp: 25}
];
var actual = findColdHot(input);
var expected = {'Coldest Place': 'Oslo','Hottest Place': 'Nairobi'};
console.log(actual)

您将最冷和最热的城市定义为 Infinity，我认为它可以解释为数字。然后将此数字与城市名称字符串值进行比较。

确保不要混合变量类型，尤其是在 JavaScript 中。

function findColdHot(array) {
  // create an empty object
  var resultObj = {};
  // create coldest and hottest variables
  let coldest = array[0];
  let hottest = array[0];
  
  // iterate over the array
  for (let i = 0; i < array.length; i++) {
    if (array[i].temp > hottest.temp) {
      hottest = array[i];
    } else if (array[i].temp < coldest.temp) {
      coldest = array[i];
    }
  }
  // create coldest and hottest properties
  resultObj['Coldest Place'] = coldest.city
  resultObj['Hottest Place'] = hottest.city;
  // return result object
  return resultObj;
}