javascript - 如何检查同一索引处的两个数组？

Question

我想确定这两个数组中有多少项匹配，然后将其作为数字存储在状态中。

例如

const [score, setScore] = React.useState(0)

const selections = ["one", "two", "three"]
const allCorrectAnswers = ["four", "two", "three"]
// this should return 2

我试过了

function checkSelectedAnswer(selections, allCorrectAnswers) {
  selections.map(eachChoice =>
    eachChoice === allCorrectAnswers.map(eachAnswer => eachAnswer) 
      ? setScore(prevScore => prevScore + 1) : 0
  )
}

如果可以，请解释为什么我的代码不能正常工作。

Answer 1

.map(在顶层或嵌套的)没有意义，因为您不是要将一个数组的每个元素转换为另一个数组。如果要使用数组方法，请改用 .reduce，并使用回调中的索引访问另一个数组中的关联元素，看是否相等。

const selections = ["one", "two", "three"];
const allCorrectAnswers = ["four", "two", "three"];
const totalCorrect = selections.reduce(
  (correctSoFar, answer, i) => correctSoFar + (answer === allCorrectAnswers[i]),
  0
);
console.log(totalCorrect);
// setScore(totalCorrect);

或者做

const selections = ["one", "two", "three"];
const allCorrectAnswers = ["four", "two", "three"];

let totalCorrect = 0;
selections.forEach((answer, i) => {
  if (answer === allCorrectAnswers[i]) {
    totalCorrect++;
  }
});
console.log(totalCorrect);
// setScore(totalCorrect);