splice(index,len,[item])它也可以用來替換/刪除/添加數組內某一個或者幾個值(該方法會改變原始數組)
index:數組開始下標
len: 替換/刪除的長度
item:替換的值,刪除操作的話 item爲空
刪除:
//刪除起始下標爲1,長度爲1的一個值(len設置1,如果爲0,則數組不變)
var arr = ['a','b','c','d'];
arr.splice(1,1);
console.log(arr);
//['a','c','d'];
//刪除起始下標爲1,長度爲2的一個值(len設置2)
var arr2 = ['a','b','c','d']
arr2.splice(1,2);
console.log(arr2);
//['a','d']
替換:
//替換起始下標爲1,長度爲1的一個值爲‘ttt’,len設置的1
var arr = ['a','b','c','d'];
arr.splice(1,1,'ttt');
console.log(arr);
//['a','ttt','c','d']
//替換起始下標爲1,長度爲2的兩個值爲‘ttt’,len設置的1
var arr2 = ['a','b','c','d'];
arr2.splice(1,2,'ttt');
console.log(arr2);
//['a','ttt','d']
添加:
//在下標爲1處添加一項'ttt'
var arr = ['a','b','c','d'];
arr.splice(1,0,'ttt');
console.log(arr);
//['a','ttt','b','c','d']