3.4数组的常用方法

「爱情、让人受尽委屈。」 2023-09-27 15:39 124阅读 0赞

数组的常用方法

<!DOCTYPE html>
    <html>
            <head>
                    <meta charset="UTF-8">
                    <title></title>
                    <script>
                            var arr=[1,2,3,4,5,6,7,8,9];
                            var index =arr.indexOf(7);//查询元素索引的方法
                            console.log(index)
                            
                            // 合并两个数组
                            var hege = ["Cecilie", "Lone"];
                            var stale = ["Emil", "Tobias", "Linus"];
                            var children = hege.concat(stale);
                            console.log(children)
                            
                            // 合并三个数组
                            var parents = ["Jani", "Tove"];
                            var brothers = ["Stale", "Kai Jim", "Borge"];
                            var children = ["Cecilie", "Lone"];
                            var family = parents.concat(brothers, children);
                            console.log(family)
                            
                            
                            // 合并字符串
                            var fruits = ["Banana", "Orange", "Apple", "Mango"];
                            var fs =fruits.join();
                            console.log(fs)
                            
                            
                            // 移除最后一个元素
                            var fruit=fruits.pop();
                            console.log(fruits)
                            console.log(fruit)
                            
                            // 想结尾增加元素
                            fruits.push("Grape");
                            console.log(fruits)
                            
                            
                            //反转数组
                            fruits.reverse();
                            console.log(fruits)
                            
                            //删除数组第一个元素
                            var ss =fruits.shift();
                            console.log(fruits);
                            console.log(ss)
                            
                            //向第一个位置添加元素
                            fruits.unshift("火龙果");
                            console.log(fruits);
                            
                            // 截取子数组  从哪个索引开始,到哪个索引结束 包头不包尾
                            
                            var citrus = fruits.slice(1,3);
                            console.log(citrus)
                            
                            var numbers =[1,2,3,4,5,6,7,8,9]
                            /*
                             * 删除数组中的某些元素
                             * 2 从哪个索引开始删除
                             * 3 删除多个少个元素
                             * */
                            /*numbers.splice(2,3);
                            console.log(numbers)*/
                            /*
                             * 如果第二个参数是0 那么就变成了在指定索引位置增加元素
                             * */
                            numbers.splice(2,0,100);
                            console.log(numbers)
                    </script>
            </head>
            <body>
            </body>
    </html>

![fcba7d38a85d065844dc9b24445cb037.gif][]

![1f42f2ebeb689c096c0a877677b1dda1.gif][]

数组元素的排序

<!DOCTYPE html>
    <html>
            <head>
                    <meta charset="UTF-8">
                    <title></title>
                    <script>
                            var fruits = ["Banana", "Orange", "Apple", "Mango"];
                            fruits.sort();
                            console.log(fruits)
                            
                            var numbers=[5,7,9,6,1,8,3,4,2];
                            numbers.sort(function(a,b){return b-a});
                            console.log(numbers)
                            
                            
                            
                    </script>
            </head>
            <body>
            </body>
    </html>

![2a7c56854083300fa029ca58a95c10ea.gif][]

![f2db8b55f9810eb64d22c843a1967d98.gif][]

[fcba7d38a85d065844dc9b24445cb037.gif]: https://img-blog.csdnimg.cn/img_convert/fcba7d38a85d065844dc9b24445cb037.gif
[1f42f2ebeb689c096c0a877677b1dda1.gif]: https://img-blog.csdnimg.cn/img_convert/1f42f2ebeb689c096c0a877677b1dda1.gif
[2a7c56854083300fa029ca58a95c10ea.gif]: https://img-blog.csdnimg.cn/img_convert/2a7c56854083300fa029ca58a95c10ea.gif
[f2db8b55f9810eb64d22c843a1967d98.gif]: https://img-blog.csdnimg.cn/img_convert/f2db8b55f9810eb64d22c843a1967d98.gif