如何提取数组中的公共元素分别放到两个数组？

Question

var arr = ["2018-04-17T03", "2018-04-18T15", "2018-04-17T04", "2018-04-18T16", "2018-04-17T05", "2018-04-18T17", "2018-04-17T06", "2018-04-17T07", "2018-04-17T08", "2018-04-17T09", "2018-04-17T20", "2018-04-18T10", "2018-04-17T21", "2018-04-18T11", "2018-04-17T00", "2018-04-17T22", "2018-04-18T12", "2018-04-17T01", "2018-04-17T23", "2018-04-18T13", "2018-04-17T02", "2018-04-18T14", "2018-04-17T14", "2018-04-18T04", "2018-04-17T15", "2018-04-18T05", "2018-04-17T16", "2018-04-18T06", "2018-04-17T17", "2018-04-18T07", "2018-04-17T18", "2018-04-18T08", "2018-04-17T19", "2018-04-18T09", "2018-04-17T10", "2018-04-18T00", "2018-04-17T11", "2018-04-18T01", "2018-04-17T12", "2018-04-18T02", "2018-04-17T13", "2018-04-18T03"];arr 中的每一个元素后三位不同，我想将每个元素前面十位相同的截取到一个数组，不同的放到另一个数组

Answer 1

const arr = ["2018-04-17T03", "2018-04-18T15", "2018-04-17T04", "2018-04-18T16", "2018-04-17T05", "2018-04-18T17", "2018-04-17T06", "2018-04-17T07", "2018-04-17T08", "2018-04-17T09", "2018-04-17T20", "2018-04-18T10", "2018-04-17T21", "2018-04-18T11", "2018-04-17T00", "2018-04-17T22", "2018-04-18T12", "2018-04-17T01", "2018-04-17T23", "2018-04-18T13", "2018-04-17T02", "2018-04-18T14", "2018-04-17T14", "2018-04-18T04", "2018-04-17T15", "2018-04-18T05", "2018-04-17T16", "2018-04-18T06", "2018-04-17T17", "2018-04-18T07", "2018-04-17T18", "2018-04-18T08", "2018-04-17T19", "2018-04-18T09", "2018-04-17T10", "2018-04-18T00", "2018-04-17T11", "2018-04-18T01", "2018-04-17T12", "2018-04-18T02", "2018-04-17T13", "2018-04-18T03"];

const prefix = '2018-04-17';  // 这个是相通的前缀，可以换

const samePrefix = []; // 存放相同前缀的数组

const others = []; // 存放不同前缀的数组

arr.forEach(date=>{

    if (date.substring(0,10) === prefix) {

        samePrefix.push(date)

    } else {

        others.push(date);

    }

})

Answer 2

var arr = ["2018-04-17T03", "2018-04-18T15", "2018-04-17T04", "2018-04-18T16", "2018-04-17T05", "2018-04-18T17", "2018-04-17T06", "2018-04-17T07", "2018-04-17T08", "2018-04-17T09", "2018-04-17T20", "2018-04-18T10", "2018-04-17T21", "2018-04-18T11", "2018-04-17T00", "2018-04-17T22", "2018-04-18T12", "2018-04-17T01", "2018-04-17T23", "2018-04-18T13", "2018-04-17T02", "2018-04-18T14", "2018-04-17T14", "2018-04-18T04", "2018-04-17T15", "2018-04-18T05", "2018-04-17T16", "2018-04-18T06", "2018-04-17T17", "2018-04-18T07", "2018-04-17T18", "2018-04-18T08", "2018-04-17T19", "2018-04-18T09", "2018-04-17T10", "2018-04-18T00", "2018-04-17T11", "2018-04-18T01", "2018-04-17T12", "2018-04-18T02", "2018-04-17T13", "2018-04-18T03"];

    const result=arr.reduce((obj,item)=>{

        const key=item.substring(0,10);

        if(!obj[key]){

            obj[key]=[];

        }

        obj[key].push(item);

        return obj;

    },{});

    const _result=Object.keys(result).map(key=>result[key]);

    console.log(_result);