📅 最后修改于: 2020-10-23 14:52:42 🧑 作者: Mango
JavaScript数组是一个对象，代表一组相似类型的元素。
使用JavaScript构造数组的3种方法
使用数组字面量创建数组的语法如下：
var arrayname=[value1,value2.....valueN];
如您所见，值包含在[]内，并以，(逗号)分隔。
让我们看一下在JavaScript中创建和使用数组的简单示例。
.length属性返回数组的长度。
上面例子的输出
Sonoo
Vimal
Ratan
直接给出创建数组的语法如下：
var arrayname=new Array();
在这里，new关键字用于创建数组实例。
让我们看看直接创建数组的示例。
上面例子的输出
Arun
Varun
John
在这里，您需要通过在构造函数中传递参数来创建数组的实例，这样我们就不必显式提供值。
下面给出了通过数组构造函数创建对象的示例。
上面例子的输出
Jai
Vijay
Smith
让我们看一下JavaScript数组方法及其说明的列表。
| Methods | Description |
|---|---|
| concat() | It returns a new array object that contains two or more merged arrays. |
| copywithin() | It copies the part of the given array with its own elements and returns the modified array. |
| entries() | It creates an iterator object and a loop that iterates over each key/value pair. |
| every() | It determines whether all the elements of an array are satisfying the provided function conditions. |
| flat() | It creates a new array carrying sub-array elements concatenated recursively till the specified depth. |
| flatMap() | It maps all array elements via mapping function, then flattens the result into a new array. |
| fill() | It fills elements into an array with static values. |
| from() | It creates a new array carrying the exact copy of another array element. |
| filter() | It returns the new array containing the elements that pass the provided function conditions. |
| find() | It returns the value of the first element in the given array that satisfies the specified condition. |
| findIndex() | It returns the index value of the first element in the given array that satisfies the specified condition. |
| forEach() | It invokes the provided function once for each element of an array. |
| includes() | It checks whether the given array contains the specified element. |
| indexOf() | It searches the specified element in the given array and returns the index of the first match. |
| isArray() | It tests if the passed value ia an array. |
| join() | It joins the elements of an array as a string. |
| keys() | It creates an iterator object that contains only the keys of the array, then loops through these keys. |
| lastIndexOf() | It searches the specified element in the given array and returns the index of the last match. |
| map() | It calls the specified function for every array element and returns the new array |
| of() | It creates a new array from a variable number of arguments, holding any type of argument. |
| pop() | It removes and returns the last element of an array. |
| push() | It adds one or more elements to the end of an array. |
| reverse() | It reverses the elements of given array. |
| reduce(function, initial) | It executes a provided function for each value from left to right and reduces the array to a single value. |
| reduceRight() | It executes a provided function for each value from right to left and reduces the array to a single value. |
| some() | It determines if any element of the array passes the test of the implemented function. |
| shift() | It removes and returns the first element of an array. |
| slice() | It returns a new array containing the copy of the part of the given array. |
| sort() | It returns the element of the given array in a sorted order. |
| splice() | It add/remove elements to/from the given array. |
| toLocaleString() | It returns a string containing all the elements of a specified array. |
| toString() | It converts the elements of a specified array into string form, without affecting the original array. |
| unshift() | It adds one or more elements in the beginning of the given array. |
| values() | It creates a new iterator object carrying values for each index in the array. |