JavaScript 删除数组中一个元素–delete与赋值为undefined方法比较

delete 删除数组一个元素

delete 删除数组的一个元素，将会把数组中该元素对应的索引一起删除, 但是数组的长度不会改变。

var arr1 = [1, 2, 3, 4, 5]; delete arr1[2]; console.log(arr1);

打印结果：

(5)[1, 2, undefined × 1, 4, 5] 0: 1 1: 2 3: 4 4: 5 length: 5

等价于：

var arr1 = [1, 2, , 4, 5];

赋值为 undefined

赋值为

var arr2 = [1, 2, 3, 4, 5]; arr2[2] = undefined; console.log(arr2);

打印结果：

(5)[1, 2, undefined, 1, 4, 5] 0: 1 1: 2 2: undefined 3: 4 4: 5 length: 5

等价于：

var arr1 = [1, 2, undefined, 4, 5];

splice 删除数组元素

var arr = [1, 2, 3, 4, 5]; // 删除数组第3个元素 arr.splice(2, 1); console.log(arr); // 1, 2, 4, 5