根据二维数组中的输入获取值

Question

我有一个二维数组

var years = [[-1,"0 years"], [1,"< 1 year"], [2,"1-3 years"], [3,"> 3 years"]];

我想根据用户输入来获取年数，这是-1,1,2,3，我该如何使用Javascript完成此操作？

我正在尝试使用years[years_input]，但没有得到正确的值。

Answer 1

尝试一下，希望它能起作用

let years = [
  [-1, "0 years"],
  [1, "< 1 year"],
  [2, "1-3 years"],
  [3, "> 3 years"]
];

function getYear(year) {

  return years.find(el => el.indexOf(year) > -1)[1]

}

console.log(getYear(-1))
console.log(getYear(1))
console.log(getYear(2))
console.log(getYear(3))

Answer 2

您可以使用find()方法。

var years = [[-1,"0 years"], [1,"< 1 year"], [2,"1-3 years"], [3,"> 3 years"]];

let input = +prompt('enter the index');
console.log(years.find(x => x[0] === input)[1])

Answer 3

获取数组的第一个元素（对于find之类的极端情况，您需要使用-1）：

const years = [[-1,"0 years"], [1,"< 1 year"], [2,"1-3 years"], [3,"> 3 years"]];
const index = 3;
const [, res] = years.find(([n]) => n == index);
console.log(res);

Answer 4

您可以使用包括：

var years = [[-1,"0 years"], [1,"< 1 year"], [2,"1-3 years"], [3,"> 3 years"]];

var input = +prompt()

for(var i = 0; i < years.length; i++) {
  if (years[i].includes(input)) {
  console.log(years[i][1])
  break
  }
}

Answer 5

您可以将Map与Map#get一起使用，并获取值的密钥。

var years = [[-1, "0 years"], [1, "< 1 year"], [2, "1-3 years"], [3, "> 3 years"]],
    yearsMap = new Map(years);

console.log(yearsMap.get(1));