数组去重四种方法展现:
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<script>
// 数组去重方法1
function unique1(arr) {
var res = arr.filter(function (item, index, array) {
return array.indexOf(item) === index
})
return res
}
console.log(unique1([1,2,3,2,1,3,4,5]));
</script>
<script>
// 方法2
function unique2(arr){
let res=[...new Set(arr)]
return res;
}
console.log(unique2([1,2,3,2,1,3,4,5]));
</script>
<script>
// 方法3
function unique3(arr){
arr.sort((a,b)=>a-b);
// console.log(arr);
for(let i=0;i<arr.length-1;i++){
if(arr[i]==arr[i+1]){
arr[i+1]=null;
}
}
return arr.filter((element=>{
return element!=null;
}))
}
console.log(unique3([1,2,3,2,1,3,4,5]));
</script>
<script>
// 方法4
function unique4(arr){
arr.sort((a,b)=>a-b);
for(let i=0;i<arr.length-1;i++){
if(arr[i]==arr[i+1]){
arr.splice(i,1);
i--;
}
}
return arr;
}
console.log(unique4([1,2,3,2,1,3,4,5]));
</script>
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