Question

我正在使用lodash对以下数组执行以下任务：

let map = {
   "John": ["math", "physics", "chem"],
   "Lisa": ["bio", "chem", "history"],
   "Emily": ["math", "history", "javascript"];
}

使用lodash，如何返回有价值的密钥＆＃34; javascript＆＃34;在它的数组中，在这种情况下是Emily？

我正在使用

_.keys(_.pickBy(map, e => {
    return (e == 'javascript');
}))

但这似乎不起作用

Answer 1

您可以使用findKey和includes方法查找密钥。

＆＃13;

let map = {
  "John": ["math", "physics", "chem"],
  "Lisa": ["bio", "chem", "history"],
  "Emily": ["math", "history", "javascript"]
}

const result = _.findKey(map, e => _.includes(e, 'javascript'))
console.log(result)

＆＃13;

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.5/lodash.js"></script>

＆＃13;

要匹配值包含元素的多个键，您可以使用pickBy方法过滤属性，然后获取键。

＆＃13;

let map = {
  "John": ["math", "physics", "chem"],
  "Lisa": ["bio", "chem", "history", "javascript"],
  "Emily": ["math", "history", "javascript"]
}

const result = _.keys(_.pickBy(map, e => _.includes(e, "javascript")))
console.log(result)

＆＃13;

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.10/lodash.js"></script>

＆＃13;

Answer 2

要使用数组格式获取所有键，请使用以下代码

let map1 = {
"John": ["math", "physics", "chem"],
"Lisa": ["bio", "chem", "history","javascript"],
"Emily": ["math", "history", "javascript"];
}

 _.compact(_.map(map1,(v,k)=>{if(v.indexOf("javascript")>-1) return k; }))

这对我来说很好。

Lodash：查找在其自己的数组中具有特定值的所有键

2 个答案: