javascript - 无法从此对象选择特定的属性值

我目前正在努力做一些简单明了的事情。我只想为该数组中的每个对象打印出特定的键值。我将不胜感激！

var countries = [

  {
    'country name': 'Australia',
    'national emblem': 'blue red white',
    'hemisphere': 'southern',
    'population': 24130000
  },
  {
    'country name': 'United States',
    'national emblem': 'blue red white',
    'hemisphere': 'northern',
    'population': 323000000
  },
  {
    'country name': 'Uzbekistan',
    'national emblem': 'blue green red white',
    'hemisphere': 'northern',
    'population': 31850000
  }

];


function getCountryprops(countries){

  for(var oneCountry in countries){
    for(var propName in oneCountry){
      console.log(oneCountry[propName]['country name'], oneCountry[propName]['population']);
    }
  }
}

所以我想最终打印出[['Australia'，24130000]，['United States'，323000000]，['Uzbekistan，31850000]]

最佳答案

在for...in数组上使用countries时，oneCountry变量是当前国家/地区的索引。要获取国家/地区，您需要在countries数组上使用方括号符号：

var countries = [{"country name":"Australia","national emblem":"blue red white","hemisphere":"southern","population":24130000},{"country name":"United States","national emblem":"blue red white","hemisphere":"northern","population":323000000},{"country name":"Uzbekistan","national emblem":"blue green red white","hemisphere":"northern","population":31850000}];

function getCountryprops(countries){
  for(var oneCountry in countries){
    console.log(countries[oneCountry]['country name'], countries[oneCountry]['population']);
  }
}

getCountryprops(countries);

另一种选择是使用for...of直接获取国家的价值：

var countries = [{"country name":"Australia","national emblem":"blue red white","hemisphere":"southern","population":24130000},{"country name":"United States","national emblem":"blue red white","hemisphere":"northern","population":323000000},{"country name":"Uzbekistan","national emblem":"blue green red white","hemisphere":"northern","population":31850000}];

function getCountryprops(countries){
  for(var oneCountry of countries){
    console.log(oneCountry['country name'], oneCountry['population']);
  }
}

getCountryprops(countries);

关于javascript - 无法从此对象选择特定的属性值，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/48967219/