你我学习网
第一种：删除最后一个元素
pop 删除
1 2 3 | var arr = [1,2,3,4,5]arr.pop() |
// arr => [1,2,3,4]
slice 删除
1 2 3 | var arr = [1,2,3,4,5]var new_arr = arr.slice(0, -1) |
// arr => [1,2,3,4,5]
// new_arr => [1,2,3,4]
1 2 3 | var arr = [1,2,3,4,5]var new_arr = arr.slice(0, arr.length - 1) |
// arr => [1,2,3,4,5]
// new_arr => [1,2,3,4]
splice 删除
1 2 3 | var arr = [1,2,3,4,5]var new_arr = arr.splice(-1) |
// arr => [1,2,3,4]
// new_arr => [5]
1 2 3 | var arr = [1,2,3,4,5]var new_arr = arr.splice(-1, 1) |
// arr => [1,2,3,4]
// new_arr => [5]
1 2 3 | var arr = [1,2,3,4,5]var new_arr = arr.splice(arr.length - 1) |
// arr => [1,2,3,4]
// new_arr => [5]
1 2 3 | var arr = [1,2,3,4,5]var new_arr = arr.splice(arr.length - 1, 1) |
// arr => [1,2,3,4]
// new_arr => [5]
for 删除
1 2 3 4 5 6 7 8 9 | var arr = [1,2,3,4,5]var new_arr = []for (let i = 0, len = arr.length; i < len; i++) { if (i < len - 1) { new_arr.push(arr[i]) }} |
// arr => [1,2,3,4,5]
// new_arr => [1,2,3,4]
length 删除
1 2 3 | var arr = [1,2,3,4,5]arr.length = arr.length - 1 |
// arr => [1,2,3,4]
第二种: 删除第一个元素
shift 删除
1 2 3 | var arr = [1,2,3,4,5]arr.shift() |
// arr => [2,3,4,5]
slice 删除
1 2 3 | var arr = [1,2,3,4,5]var new_arr = arr.slice(1) |
// arr => [1,2,3,4,5]
// new_arr => [2,3,4,5]
splice 删除
1 2 3 | var arr = [1,2,3,4,5]var new_arr = arr.splice(0, 1) |
// arr => [2,3,4,5]
// new_arr => [1]
第三种：删除数组中某个指定下标的元素
splice 删除
1 2 3 | var delete_index = 2var arr = [1,2,3,4,5] |
// arr => [1,2,3,4,5]
1 | var new_arr = arr.splice(delete_index, 1) |
// new_arr => [3]
// arr => [1,2,4,5]
for 删除
1 2 3 4 5 6 7 8 9 | var delete_index = 2, arr = [1,2,3,4,5], new_arr = []for (let i = 0, len = arr.length; i < len; i++) { if (i != delete_index) { new_arr.push(arr[i]) }} |
// arr => [1,2,3,4,5]
// new_arr => [1,2,4,5]
注意：
1. 不可以使用 delete 方式删除数组中某个元素，此操作会造成稀疏数组，被删除的元素的为位置依然存在为empty，且数组的长度不变
2. 不可以使用 forEach 方法比对数组下标值，因为 forEach 在循环的时候是无序的
第四种：删除数组中某个指定元素的元素
splice 删除
1 2 3 4 | var element = 2, arr = [1,2,3,4,5]arr.splice(arr.indexOf(2), 1) |
// arr => [1,3,4,5]
filter 删除
1 2 3 4 | var arr = [1,2,3,4,5], element = 2arr = arr.filter(item => item != element) |
// arr => [1,3,4,5]
forEach、map、for 删除
1 2 3 4 5 | var arr = [1,2,3,4,5], element = 2, new_arr = []arr.forEach(item => (item != element && new_arr.push(item))) |
// new_arr => [1,3,4,5]
// map 同理
1 2 3 4 5 6 7 | var arr = [1,2,3,4,5], element = 2, new_arr = []for (let i = 0; i < arr.length; i++) { arr[i] != element && new_arr.push(arr[i])} |
// new_arr => [1,3,4,5]
Set 删除
1 2 3 4 5 6 | var arr = [1,2,3,4,5], element = 2var new_set = new Set(arr)new_set.delete(element)var new_arr = [...new_set] |
// new_arr => [1,3,4,5]
