JS如何return表示居住在一个城市的人数？

Question

我是编码新手，收到了这个问题，但我似乎无法使我的代码正常工作。有人有什么建议吗？

这是我得到的问题：

此函数接收一组人物对象，格式为：

[{ name: 'Sandra', lives: { country: 'UK', city: 'Manchester' }, age: 32 }]

该函数应该return居住在瓦伦西亚市的人数

这是我编写的代码；

function countPeopleInValencia(people) {
let count = 0
for (let i = 0; i < people.length; i++) {
  if (people.city[i] === 'Valencia') {
    count ++ }
  else {return 0}
  }
  return count
}

这就是我的代码运行反对的内容；

describe("countPeopleInValencia", () => {
it("returns 0 when nobody is from Valencia", () => {
expect(
  countPeopleInValencia([
    {
      name: "Sandra",
      lives: { country: "UK", city: "Manchester" },
      age: 32
    },
    {
      name: "Sandrella",
      lives: { country: "Spain", city: "Bilbao" },
      age: 32.5
    }
  ])
).to.equal(0);
  });
  it("returns the length of the array when everyone is from Valencia",   () => {
  expect(
  countPeopleInValencia([
    {
      name: "Cassandra",
      lives: { country: "Spain", city: "Valencia" },
      age: 32.5
    },
    {
      name: "Cassandrella",
      lives: { country: "Spain", city: "Valencia" },
      age: 35.55
    }
  ])
).to.equal(2);
 });
it("returns the number of people who are actually from the fair city of Valencia", () => {
expect(
  countPeopleInValencia([
    {
      name: "Melissandra",
      lives: { country: "Spain", city: "Valencia" },
      age: 55.5
    },
    {
      name: "Melissandrella",
      lives: { country: "Spain", city: "Valencia" },
      age: 55.555
    },
    {
      name: "Keith",
      lives: { country: "UK", city: "Newport Pagnell" },
      age: 2
    }
  ])
).to.eql(2);
expect(
  countPeopleInValencia([
    {
      name: "Imeldarina",
      lives: { country: "Spain", city: "Valencia" },
      age: 15.2
    },
    {
      name: "Bob",
      lives: { country: "Wales", city: "Abertillery" },
      age: 555555555555.555
    },
    {
      name: "Terry",
      lives: { country: "England", city: "Newport Pagnell" },
      age: 0.00000002
    }
  ])
).to.equal(1);
});
});

Answer 1

在您当前的代码中，您 return 一旦找到不在您要计算的城市的人，您就会计算值

function countPeopleInValencia(people) {
    let count = 0
    for (let i = 0; i < people.length; i++) {
        if (people.city[i] === 'Valencia') {
             count ++ 
        }
    }
    return count
}

Answer 2

除了将计数移到 for 循环之外，您还应该更正

people.city[i]

至

people[i]['lives']['city']

你的函数：

function countPeopleInValencia(people) {
  let count = 0
  for (let i = 0; i < people.length; i++) {
    if (people[i]['lives']['city'] === 'Valencia') {
      count++;
    }
  }
  return count
}

JS如何return表示居住在一个城市的人数？

JS how to return the amount of people that live in a city?

javascript

arrays

javascript-objects

city