数组去重
手写数组去重
function removeDup(arr){
let result = []
let hashMap = {}
for(let i = 0; i < arr.length; i++){
let temp = arr[i]
if(!hashMap[temp]){
hashMap[temp] = true
result.push(temp)
}
}
return result
}
Array.from搭配Set
Array.from(new Set(arr))
扩展字符串搭配Set
[...new Set(arr)]
数组乱序
let arr = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
arr.sort(function () {
return Math.random() - 0.5
})