1 length:长度
<script> var arr = [1,2,3,4,5,6,7,8]; console.log(arr.length);//arr.length = 8; arr.length = 5;//给定数组长度; console.log(arr);//arr = [1,2,3,4,5]; delete arr[2];//删除arr[2],数组长度不变; console.log(arr);//arr = [1, 2, empty, 4, 5]; console.log(typeof(arr[2]));//undefined; console.log(arr.length); </script>
2 pop,push:方法,把数组相当于一个栈
push(x):向数组尾部压入x,并返回新数组的长度
pop():从尾部弹出一个元素,并返回弹出的元素
<script> var arr = [1,2,3,4,5]; var number = arr.push(7);//arr.push(9) 相当于 arr[arr.length] = 7; console.log(arr);//arr = [1,2,3,4,5,7] console.log(number);//6 var num = arr.pop(); console.log(arr);// arr = [1,2,3,4,5] console.log(num);//7 </script>
3 unshift 和 shift 方法,把数组相当于一个队列
unshift(x):向数组头部插入x,并返回数组长度
shift():从头部弹出一个元素,并返回弹出的元素
<script> var arr = [1,2,3,4,5]; var number = arr.unshift(9); console.log(arr);// arr = [9,1,2,3,4,5]; console.log(number);// 6 var num = arr.shift(); console.log(arr);// arr = [1,2,3,4,5]; console.log(num);//9 </script>
4 slice 和 splice 方法
slice(x,y):返回数组[x,y),索引位置的片段,左从0开始,右从-1开始,不影响原数组
splice(x,y,[.....]):x:删除的起始位置,y删除的个数(没有y的话,删除起始点开始所有),[...]为要插入数组的所有参数;splice方法改变原数组
<script> var arr = [1,2,3,4,5]; console.log(arr.slice(1,3));//[2, 3] console.log(arr);// [1,2,3,4,5] console.log(arr.slice(1));//[2, 3, 4, 5] console.log(arr.length);//5 console.log(arr.slice(0,-1));//[1, 2, 3, 4] var arr1 = [1,2,3,4,5,6]; console.log(arr1.splice(1,2));//[2, 3] console.log(arr1);//[1, 4, 5, 6] console.log(arr1.splice(0));//[1, 4, 5, 6] console.log(arr1);//[] arr1 = [1,6] console.log(arr1.splice(0,1,1,2,3,‘4‘,‘5‘));//[1] console.log(arr1);//[1, 2, 3, "4", "5", 6] </script>
待后续补充........
原文:https://www.cnblogs.com/Zxq-zn/p/11469824.html