如何返回对象中的属性并按顺序排列它们？

Question

鉴于这两个数组：var amounts = [9, 1, 8, 16, 5, 1, 42]var animals = ["ducks", "elephants", "pangolins", "zebras", "giraffes", "penguins", "llamas"]我必须编写一个函数，它接受两个变量并返回一个组合字符串。预期的输出是："9 ducks 1 elephants 8 pangolins 16 zebras 5 giraffes 1 penguins 42 llamas"我创建了一个类似于预期字符串的对象。我现在需要按该顺序打印属性。function animalsAmounts(arr1, arr2){    let object = {};    arr2.forEach((arr2, i) => object[arr2] = arr1[i]);    return object    let result = Object.keys(object).map(function(key) {        return [Number(key), obj[key]];    }); return result}console.log(animalsAmounts(amounts, animals))它打印：{ ducks: 9,  elephants: 1,  pangolins: 8,  zebras: 16,  giraffes: 5,  penguins: 1,  llamas: 42 }我不知道如何将预期结果作为字符串返回。我尝试了各种方法来记录数量和动物，但只能返回一种或另一种。

Answer 1

Array.prototype.join()从数组的项目中创建一个字符串，将它们与您选择的任何内容连接起来。

animals.map((a, i) => `${amounts[i]} ${a}`).join(" ")

var amounts = [9, 1, 8, 16, 5, 1, 42]

var animals = ["ducks", "elephants", "pangolins", "zebras", "giraffes", "penguins", "llamas"]

console.log(animals.map((a, i) => `${amounts[i]} ${a}`).join(" "))

Answer 2

您可以对同一索引处的任意数组和映射值采用动态方法，然后再连接到单个字符串。

var amounts = [9, 1, 8, 16, 5, 1, 42]

var animals = ["ducks", "elephants", "pangolins", "zebras", "giraffes", "penguins", "llamas"],

    result = [amounts, animals]

        .reduce((r, a) => a.map((v, i) => (r[i] ? r[i] + ' ' : '') + v), [])

        .join(' ');

console.log(result);