JavaScript: el objeto Arrays
los ArrayEl objeto le permite almacenar varios valores en una sola variable. Almacena una colección secuencial de tamaño fijo de elementos del mismo tipo. Una matriz se utiliza para almacenar una colección de datos, pero a menudo es más útil pensar en una matriz como una colección de variables del mismo tipo.
Sintaxis
Utilice la siguiente sintaxis para crear un Array objeto -
var fruits = new Array( "apple", "orange", "mango" );
los ArrayEl parámetro es una lista de cadenas o números enteros. Cuando especifica un único parámetro numérico con el constructor Array, especifica la longitud inicial de la matriz. La longitud máxima permitida para una matriz es 4.294.967.295.
Puede crear una matriz simplemente asignando valores de la siguiente manera:
var fruits = [ "apple", "orange", "mango" ];
Utilizará números ordinales para acceder y establecer valores dentro de una matriz de la siguiente manera.
fruits[0] is the first element
fruits[1] is the second element
fruits[2] is the third element
Propiedades de matriz
Aquí hay una lista de las propiedades del objeto Array junto con su descripción.
No Señor. | Descripción de propiedad |
---|---|
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. |
In the following sections, we will have a few examples to illustrate the usage of Array properties.
Array Methods
Here is a list of the methods of the Array object along with their description.
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. |
In the following sections, we will have a few examples to demonstrate the usage of Array methods.