js数组练习

把数字变成星期

let arr = [0,1,2,2,3,3,3,4,4,4,4,6] let arr2 = arr.map(补全代码) console.log(arr2) // ['周日', '周一', '周二', '周二', '周三', '周三', '周三', '周四', '周四', '周四', '周四','周六']

请使用 arr.map 把 0 变成'周日'，把 1 变成'周一'，以此类推

let arr = [0,1,2,2,3,3,3,4,4,4,4,6]
let arr2 = arr.map((i)=>{
  const hash = {0:'周日',1:'周一',2:'周二',3:'周三',4:'周四',5:'周五',6:'周六'}
  return hash[i]
})
console.log(arr2)

找出所有大于 60 分的成绩

let scores = [95,91,59,55,42,82,72,85,67,66,55,91] let scores2 = scores.filter(补全代码) console.log(scores2) //  [95,91,82,72,85,67,66, 91]

let scores = [95,91,59,55,42,82,72,85,67,66,55,91]
let scores2 = scores.filter((item)=>item > 60)
console.log(scores2) // [95,91,82,72,85,67,66, 91]

算出所有奇数之和

let scores = [95,91,59,55,42,82,72,85,67,66,55,91] let sum = scores.reduce((sum, n)=>{ 补全代码 },0) console.log(sum) // 奇数之和：598

let scores = [95,91,59,55,42,82,72,85,67,66,55,91]
let sum = scores.reduce((sum, n)=>{
return n%2===0?sum:sum+n
},0)
console.log(sum) // 奇数之和：598