问题描述
我有两个数组,例如:
arr1 = ["orange","banana"]
arr2 = [{"fruit"= ["pineapple","banana"]},{"fruit"= ["grapes","apple"]},{"fruit"= ["apple","orange"]}]
我需要过滤第二个数组中是否存在第一个元素。
我正在尝试这样做:
let kFilter = arr1.map(itemY => { return itemY; });
let filteredK = arr2.filter(itemX => kFilter.includes(itemX.fruit));
但没有成功:-(
解决方法
//declaration variables correctly
let arr1 = ["orange","banana"]
let arr2 = [{"fruit" : ["pineapple","banana"]},{"fruit" : ["grapes","apple"]},{"fruit": ["apple","orange"]}];
//filter using reduce
arr2.filter((e)=>arr1.reduce((a,i)=>a||e["fruit"].includes(i),false))
//filter using some
arr2.filter((e)=>arr1.some((i)=>e["fruit"].includes(i)))
,
首先为了避免过多的迭代,将简单数组转换为如下所示的对象。否则复杂度会很高
const fruitMap = {
"orange": 1,"banana": 1
};
然后你必须遍历第二个数组中的每个项目
arr2.forEach(fruitsObj => {
let arr = fruitsObj['fruit'];
for (let i = 0; i < arr.length(); i ++) {
if (fruitMap[arr[i]]) {
arr.splice(i,1);
}
}
})