数组去重的方法

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<script src="./js/underscore.js"></script>
<script>
function getNewArr(arr){
let res = _.uniq(arr)
return res
}
console.log(getNewArr([1,4,5,7,3,4,1,0,5,6,5,3,1]))
</script>

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<script>
function getNewArr(arr){
//new Set(arr) 把数组转化为不重复的对象
//Array.from() 再把对象转化为数组
return Array.from(new Set(arr))
}
console.log(getNewArr([1,4,5,7,3,4,1,0,5,6,5,3,1]))
</script>

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<script>
function getNewArr(arr){
return [...new Set(arr)]
}
console.log(getNewArr([1,4,5,7,3,4,1,0,5,6,5,3,1]))
</script>

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<script>
function getNewArr(arr){
let res =[]
arr.forEach((item,index)=>{
if(arr.indexOf(item)===-1){
res.push(item)
}
})
return res
}
console.log(getNewArr([1,4,5,7,3,4,1,0,5,6,5,3,1]))
</script>

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<script>
function getNewArr(arr){
//过滤数组中下标不唯一的元素
//Array.from() 再把对象转化为数组
return arr.filter((item,index)=>arr.indexOf(item)===index)
}
console.log(getNewArr([1,4,5,7,3,4,1,0,5,6,5,3,1]))
</script>

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<script>
function getNewArr(arr){
//reduce
return arr.reduce((pre,next)=>{
return
pre.includes(next)?pre:[...pre,next]
},[])
}
console.log(getNewArr([1,4,5,7,3,4,1,0,5,6,5,3,1]))
</script>

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function getNewArr(arr){
let res = {}
arr.forEach((item,index)=>res[arr[index]] = item)//利用对象key值唯一
return Object.keys(res).map(item => ~~item)
}
console.log(getNewArr([1,4,5,7,3,4,1,0,5,6,5,3,1]))
</script>

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<script>
function getNewArr(arr){
let res = [] ;
let temp = arr.sort()
for(let i = 0; i < temp.length; i++){
if(temp[i]!==temp[i+1]){
res.push(arr[i])
}
}
return res
}
console.log(getNewArr([1,4,5,7,3,4,1,0,5,6,5,3,1]))
</script>