Question

我有以下对象：

{
  apple: 0,
  banana: 0,
  cherry: 0,
  date: 0,

and so on...
}

还有一串字符串，它们是烹饪书中的单词。

[0] => "the"
[1] => "apple"
[2] => "and"
[3] => "cherry"

以此类推...

我想遍历字符串数组，并在每次上述键作为字符串提及时添加+1吗？我一直在尝试使用object.keys，但是无法使其正常工作？

这是在node.js中。

Answer 1

您可以执行类似以下的简单操作，这将绝对增加字符串数组中的所有键：

let ingredients = {
  apple: 0,
  banana: 0,
  cherry: 0,
  date: 0,
  // and more...
}

let arr = ["the","apple","and","cherry"]

// loop through array, incrementing keys found
arr.forEach((ingredient) => {
  if (ingredients[ingredient]) ingredients[ingredient] += 1;
  else ingredients[ingredient] = 1
})

console.log(ingredients)

但是，如果要仅设置的ingredients对象中的键，可以执行以下操作：

let ingredients = {
  apple: 0,
  banana: 0,
  cherry: 0,
  date: 0,
  // and more...
}

let arr = ["the","apple","and","cherry"]

// loop through array, incrementing keys found
arr.forEach((ingredient) => {
  if (ingredients[ingredient] !== undefined)
    ingredients[ingredient] += 1;
})

console.log(ingredients)

Answer 2

使用数组filter和some处理它的另一种方法：

var fruits = {
  apple: 0,
  banana: 0,
  cherry: 0,
  date: 0,
};

const words = ["the", "apple", "and", "cherry"];

var filtered = words.filter(word => Object.keys(fruits).includes(word));
filtered.forEach(fruit => fruits[fruit] += 1);

// fruits
// {apple: 1, banana: 0, cherry: 1, date: 0}
console.log(fruits);

Answer 3

您可以使用reduce对其进行简化。

const words = ["the", "apple", "and", "cherry"];

let conts = {
  apple: 0,
  banana: 0,
  cherry: 0,
  date: 0,
};
const result = words.reduce((map, word) => {
  if (typeof map[word] !== "undefined") map[word] += 1;
  return map;
}, conts);
console.log(result);

检查字符串数组是否包含对象键

3 个答案: