从 JSON 文件获取特定键/值对的数组

Question

初学者 - 我想从 JSON 文件为我的世界城市类型提前项目创建一个数组。我已经获取了数据，现在我想提取 2 个键/值对（称为名称/国家/地区）并将它们推送到一个新的字符串数组中，该数组的语法如下：

const arr = ["name, country", "name, country", "name, country"...]

以下是数据示例：

[]:

0: {country: "Andorra", geonameid: 3040051, name: "les Escaldes", subcountry: "Escaldes-Engordany"}

1: {country: "Andorra", geonameid: 3041563, name: "Andorra la Vella", subcountry: "Andorra la Vella"}

2: {country: "United Arab Emirates", geonameid: 290594, name: "Umm al Qaywayn", subcountry: "Umm al Qaywayn"}

3: {country: "United Arab Emirates", geonameid: 291074, name: "Ras al-Khaimah", subcountry: "Raʼs al Khaymah"}...

我知道我必须使用.push()and.forEach()或 for 循环，但我不知道如何去做。谁能告诉我怎么做？

Answer 1

map像这样使用：const arr = data.map(city => city.name + ", " + city.country);arrdata将是一个与 in中的每个city对象data映射到 string 的长度相同的新数组city.name + ", " + city.country。演示：const data = [ {country: "Andorra", geonameid: 3040051, name: "les Escaldes", subcountry: "Escaldes-Engordany"}, {country: "Andorra", geonameid: 3041563, name: "Andorra la Vella", subcountry: "Andorra la Vella"}, {country: "United Arab Emirates", geonameid: 290594, name: "Umm al Qaywayn", subcountry: "Umm al Qaywayn"}, {country: "United Arab Emirates", geonameid: 291074, name: "Ras al-Khaimah", subcountry: "Raʼs al Khaymah"} ];const arr = data.map(city => city.name + ", " + city.country);console.log(arr);

Answer 2

const data = [{country: "Andorra", geonameid: 3040051, name: "les Escaldes", subcountry: "Escaldes-Engordany"},{country: "Andorra", geonameid: 3041563, name: "Andorra la Vella", subcountry: "Andorra la Vella"},{country: "United Arab Emirates", geonameid: 290594, name: "Umm al Qaywayn", subcountry: "Umm al Qaywayn"},{country: "United Arab Emirates", geonameid: 291074, name: "Ras al-Khaimah", subcountry: "Raʼs al Khaymah"}]const arr = data.map(i => `${i.name} , ${i.country}`);console.log(arr)

Answer 3

forEach 的简单解决方案countries = [  {country: "Andorra", geonameid: 3040051, name: "les Escaldes", subcountry: "Escaldes-Engordany"},  {country: "Andorra", geonameid: 3041563, name: "Andorra la Vella", subcountry: "Andorra la Vella"},  {country: "United Arab Emirates", geonameid: 290594, name: "Umm al Qaywayn", subcountry: "Umm al Qaywayn"},  {country: "United Arab Emirates", geonameid: 291074, name: "Ras al-Khaimah", subcountry: "Raʼs al Khaymah"}]let arr = [];let result = [];countries.forEach((country, index) => {    let nameStr = `${country.name}, ${country.country}`    result.push(nameStr);})console.log(result)//output//["les Escaldes Andorra", "Andorra la Vella Andorra", "Umm al Qaywayn United Arab Emirates", "Ras al-Khaimah United Arab Emirates"]

Answer 4

如果您愿意，可以使用reduce函数：arr.reduce((acc, curr) => [...acc, (`${curr.name}, ${curr.country}`)], []);它将以您想要的格式返回您的值。下面的例子。const arr = [    {country: 'Andorra', geonameid: 3040051, name: 'les 1', subcountry: 'Escaldes-Engordany'},    {country: 'Turkey', geonameid: 3040021, name: 'les Escaldes', subcountry: 'aaaa'},    {country: 'IDK', geonameid: 3040021, name: 'Wow', subcountry: 'aaaa'}];const custom = arr.reduce((acc, curr) => [...acc, (`${curr.name}, ${curr.country}`)], []);console.log(custom);