前端入门-JS数组-数组翻转

const arr= [1,2,3,4,5,6];
for(let i = 0; i < arr.length / 2; i++){
    const flag = arr[i];
    arr[i] = arr[arr.length -1 -i];
    arr[arr.length -1 -i]= flag;
}
console.log(arr);  // [6, 5, 4, 3, 2, 1]

const arr= [1,2,3,4,5,6];
const exchange = (arr, length, index) => {
    arr[index] = arr.splice(length, 1, arr[index])[0];
}
for(let i = 0; i < arr.length / 2; i++){
   exchange(arr, arr.length -1 -i, i);
}
console.log(arr);  // [6, 5, 4, 3, 2, 1]