js中数组和字符串的方法总结

一、数组方法简单总结为以下几种

　　1、原有：　　　　　增、删、改、截、拼、复、排、转

　　2、ES5扩展：　　　查、遍历

增：

　　　　　　　前增
            var arr = [3,4,5,6,7];
            console.log(arr.unshift(1,2,[true,false]));        //8
            console.log(arr);                                //Array(8) [ 1, 2, (2) […], 3, 4, 5, 6, 7 ]


            后增
            var arr = [3,4,5,6,7];
            console.log(arr.push(1,2,[true,false]));        //8
            console.log(arr);                                //Array(8) [ 3, 4, 5, 6, 7, 1, 2, (2) […] ]

删：

            前删
            var arr = [3,4,5,6,7];                            //3 删除的元素
            console.log(arr.shift());                        //Array(4) [ 4, 5, 6, 7 ]
            console.log(arr);
            后删
            var arr = [3,4,5,6,7];                            
            console.log(arr);
            console.log(arr.pop());                            //7
            console.log(arr);                                //Array(4) [ 3, 4, 5, 6 ] 

改：

            改
            var arr = [3,4,5,6,7];                            //
            console.log(arr);
            console.log(arr.splice(1,2)); //从下标1开始，删除2个元素    //Array [ 4, 5 ]
            console.log(arr);                                            //Array(3) [ 3, 6, 7 ]
            
            var arr = [3,4,5,6,7];
            console.log(arr);
            console.log(arr.splice(1,2,8,9,[true,false,null])); //Array [ 4, 5 ]        //把4,5改成8,9,[true,false,null]
            console.log(arr);                                    //Array(6) [ 3, 8, 9, (3) […], 6, 7 ]
            
            var arr = [3,4,5,6,7];
            console.log(arr);
            console.log(arr.splice(1,2,8,9,[true,false,null]));    //Array [ 4, 5 ]
            console.log(arr);                                    //Array(6) [ 3, 8, 9, (3) […], 6, 7 ]
            
            var arr = [3,4,5,6,7];
            console.log(arr);
            console.log(arr.splice(1,0,8,9,[true,false,null])); //Array []
            console.log(arr);                                    //Array(8) [ 3, 8, 9, (3) […], 4, 5, 6, 7 ]

截：