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📜  JavaScript-数组对象

📅  最后修改于: 2020-12-18 05:02:45             🧑  作者: Mango

Array对象使您可以将多个值存储在单个变量中。它存储相同类型元素的固定大小的顺序集合。数组用于存储数据的集合，但是将数组视为相同类型的变量的集合通常会更有用。

句法

使用以下语法创建Array对象-

var fruits = new Array( "apple", "orange", "mango" );

Array参数是字符串或整数的列表。当您使用Array构造函数指定单个数字参数时，您将指定数组的初始长度。数组允许的最大长度为4,294,967,295。

您可以通过简单地分配值来创建数组，如下所示：

var fruits = [ "apple", "orange", "mango" ];

您将使用序数来访问和设置数组内的值，如下所示。

fruits[0] is the first element
fruits[1] is the second element
fruits[2] is the third element

数组属性

这是Array对象的属性及其描述的列表。

Sr.No. Property & Description
1 constructor

Returns a reference to the array function that created the object.
2

index

The property represents the zero-based index of the match in the string
3

input

This property is only present in arrays created by regular expression matches.
4 length

Reflects the number of elements in an array.
5 prototype

The prototype property allows you to add properties and methods to an object.

在以下各节中，我们将通过一些示例来说明Array属性的用法。

数组方法

这是Array对象的方法及其说明的列表。

Sr.No. Method & Description
1 concat()

Returns a new array comprised of this array joined with other array(s) and/or value(s).
2 every()

Returns true if every element in this array satisfies the provided testing function.
3 filter()

Creates a new array with all of the elements of this array for which the provided filtering function returns true.
4 forEach()

Calls a function for each element in the array.
5 indexOf()

Returns the first (least) index of an element within the array equal to the specified value, or -1 if none is found.
6 join()

Joins all elements of an array into a string.
7 lastIndexOf()

Returns the last (greatest) index of an element within the array equal to the specified value, or -1 if none is found.
8 map()

Creates a new array with the results of calling a provided function on every element in this array.
9 pop()

Removes the last element from an array and returns that element.
10 push()

Adds one or more elements to the end of an array and returns the new length of the array.
11 reduce()

Apply a function simultaneously against two values of the array (from left-to-right) as to reduce it to a single value.
12 reduceRight()

Apply a function simultaneously against two values of the array (from right-to-left) as to reduce it to a single value.
13 reverse()

Reverses the order of the elements of an array — the first becomes the last, and the last becomes the first.
14 shift()

Removes the first element from an array and returns that element.
15 slice()

Extracts a section of an array and returns a new array.
16 some()

Returns true if at least one element in this array satisfies the provided testing function.
17 toSource()

Represents the source code of an object
18 sort()

Sorts the elements of an array
19 splice()

Adds and/or removes elements from an array.
20 toString()

Returns a string representing the array and its elements.
21 unshift()

Adds one or more elements to the front of an array and returns the new length of the array.

在以下各节中，我们将通过一些示例来演示Array方法的用法。