1、push()方法可向数组的末尾添加一个或多个元素,并返回新的长度。
1)、语法:
arrayObject.push(newelement1,newelement2,....,newelementX)
2)、返回值:
把指定的值添加到数组后的新长度。
3)、说明:
push() 方法可把它的参数顺序添加到 arrayObject 的尾部。它直接修改 arrayObject,而不是创建一个新的数组。
4)、实例:
var arr = new Array(3)arr[0] = "ZhangQian"arr[1] = "LinFang"arr[2] = "HaiKun"console.log(arr);// ["ZhangQian","LinFang","HaiKun"]console.log(arr.push("C"));// 4console.log(arr);// ["ZhangQian","LinFang","HaiKun","C"]console.log(arr.push("A","B"));// 6console.log(arr);// ["ZhangQian","LinFang","HaiKun","A","B","C"]
2、unshift()方法可向数组的开头添加一个或更多元素,并返回新的长度。
1)、语法:
arrayObject.unshift(newelement1,newelement2,....,newelementX)
2)、返回值:
arrayObject 的新长度。
3)、说明:
unshift() 方法将把它的参数插入 arrayObject 的头部,并将已经存在的元素顺次地移到较高的下标处,以便留出空间。该方法的第一个参数将成为数组的新元素 0,如果还有第二个参数,它将成为新的元素 1,以此类推。
请注意,unshift() 方法不创建新的数组,而是直接修改原有的数组。
4)、实例:
var arr = new Array(3)arr[0] = "ZhangQian"arr[1] = "LinFang"arr[2] = "HaiKun"console.log(arr);// ["ZhangQian","LinFang","HaiKun"]console.log(arr.unshift("C"));// 4console.log(arr);// ["C","ZhangQian","LinFang","HaiKun"]console.log(arr.unshift("A","B"));// 6console.log(arr);// ["A","B","C","ZhangQian","LinFang","HaiKun"]
3、splice()方法向/从数组中添加/删除项目,然后返回被删除的项目。
1)、语法:
arrayObject.splice(index,howmany,item1,.....,itemX)
2)、返回值:
3)、说明:
splice() 方法可删除从 index 处开始的零个或多个元素,并且用参数列表中声明的一个或多个值来替换那些被删除的元素。
如果从 arrayObject 中删除了元素,则返回的是含有被删除的元素的数组。
splice() 方法会直接对数组进行修改。
4)、实例:
var arr = ["A","ZhangQian","LinFang","HaiKun"];console.log(arr.splice(1,0,"B","C"));// []console.log(arr);// ["A","B","C","ZhangQian","LinFang","HaiKun"]console.log(arr.splice(1,2));// ["B","C"]console.log(arr);// ["A","ZhangQian","LinFang","HaiKun"]console.log(arr.splice(1,1,"D"));// ["ZhangQian"]console.log(arr);// ["A","D","LinFang","HaiKun"]
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