假設數組arr有n個元素,現在要刪掉下標爲index的元素
有兩種方法:
1.splice:刪除後,後面的元素自動填補到前面
arr.splice(index, 1);
例子://arr=['a','b','c','d']
arr.splice(1, 1);//結果arr=['a','c','d'](下標1開始,刪除1個)
補充:
spice增加:arr.splice(1,0,'str'); //結果arr=['a','str','b','c','d']
spice替換:arr.splice(1,1,'str'); //結果arr=['a','str','c','d']
spice替換2:arr.splice(1,2,'str'); //結果arr=['a','str','d'](就是說:下標1開始2個換成1個“str”)
spice刪除多個:arr.splice(1,2); //結果arr=['a','d']
2.delete:刪除後,該下標位置元素爲undefined
delete arr[index];
//結果arr=['a',undefined,'c','d']