数组方法2let arr = [10,20,111,222,444,40,50] let arr = [10,20,11

let arr = [10,20,111,222,444,40,50]

// 1:取出小于100的数字
let newarr = arr.filter(n => n<100)
   console.log(newarr);
//2. 将所有小于100的乘以2
     let new2arr = newarr.map(n => n*2)
 console.log(new2arr);


// 3.将2中所有的数相加
 let totalarr = new2arr.reduce((m,n) => m + n,0)
  console.log(totalarr);

  // 一步到位
  let total = arr.filter(n => n<100).map(n => n*2).reduce((m,n) => m+n,0 )
  console.log(total);