Array.splice()理解记忆

var arr = [0,1,2,3,4,5,6,7,8,9];
arr.splice(0,0,"添加项1"); //arr => ["添加项",0,1,2,3,4,5,6,7,8,9]
arr.splice(0,2,"添加项2","添加项3")//arr => ["添加项2","添加项3",1,2,3,4,5,6,7,8,9]

Array.splice() 用途:插入/删除和替换数组元素.

array.splice(start,deleteCount,value,...)

从数组索引为start的项开始,添加value1,value2.... ,

然后从新添加的最后一项的索引开始,删除其后的deleteCount项元素,不包括新添加的项;

若deleteCount为0,则不删除,只添加.

返回值

如果从array中删除了元素,则返回由删除元素组成的新数组