--- title: Array slug: Web/JavaScript/Reference/Global_Objects/Array tags: - Global Objects - JavaScript - NeedsTranslation - Reference - TopicStub - דוגמא - מערך translation_of: Web/JavaScript/Reference/Global_Objects/Array ---

האובייקט מערך(Array) בג'אווה סקריפט הוא אובייקט גלובלי אשר משמש לבניית מערכים שהם אובייקטים דמויי רשימה .

צור מערך

var fruits = ["Apple", "Banana"];

console.log(fruits.length);
// 2

קבל גישה לאיבר(ע"י האינדקס שלו) במערך

var first = fruits[0];
// Apple

var last = fruits[fruits.length - 1];
// Banana

השתמש בלולאה על המערך

fruits.forEach(function (item, index, array) {
  console.log(item, index);
});
// Apple 0
// Banana 1

הוסף איבר לסוף המערך

var newLength = fruits.push("Orange");
// ["Apple", "Banana", "Orange"]

הסר את האיבר האחרון במערך

var last = fruits.pop(); // remove Orange (from the end)
// ["Apple", "Banana"];

הסר איבר הראשון מערך

var first = fruits.shift(); // remove Apple from the front
// ["Banana"];

הוסף איבר לראשית המערך

var newLength = fruits.unshift("Strawberry") // add to the front
// ["Strawberry", "Banana"];

מצא את האינדקס של איבר במערך

fruits.push("Mango");
// ["Strawberry", "Banana", "Mango"]

var pos = fruits.indexOf("Banana");
// 1

הסר איבר על ידי האינדקס(מיקום) שלו

var removedItem = fruits.splice(pos, 1); // this is how to remove an item
// ["Strawberry", "Mango"]

צור עותק של המערך

var shallowCopy = fruits.slice(); // this is how to make a copy
// ["Strawberry", "Mango"]

תחביר

[element0, element1, ..., elementN]
new Array(element0, element1[, ...[, elementN]])
new Array(arrayLength)

פרמטרים

elementN: A JavaScript array is initialized with the given elements, except in the case where a single argument is passed to the Array constructor and that argument is a number (see the arrayLength parameter below).Note that this special case only applies to JavaScript arrays created with the Array constructor, not array literals created with the bracket syntax.
arrayLength: If the only argument passed to the Array constructor is an integer between 0 and 2³²-1 (inclusive), this returns a new JavaScript array with length set to that number. If the argument is any other number, a {{jsxref("RangeError")}} exception is thrown.

Description

Arrays are list-like objects whose prototype has methods to perform traversal and mutation operations. Neither the length of a JavaScript array nor the types of its elements are fixed. Since an array's length can change at any time, and data can be stored at non-contiguous locations in the array, JavaScript arrays are not guaranteed to be dense; this depends on how the programmer chooses to use them. In general, these are convenient characteristics; but if these features are not desirable for your particular use, you might consider using typed arrays.

Some people think that you shouldn't use an array as an associative array. In any case, you can use plain {{jsxref("Global_Objects/Object", "objects")}} instead, although doing so comes with its own caveats. See the post Lightweight JavaScript dictionaries with arbitrary keys as an example.

גישה לאלמנטים שבמערך

מערכים ב - JavaScript מסודרים לפי מספרים מאפס ומעלה: מספרו של האיבר הראשון במערך הוא 0 ומספרו של האיבר האחרון במערך שווה לכמות האיברים במערך (אורכו של המערך - Array.length) פחות 1.

var arr = ['this is the first element', 'this is the second element'];
console.log(arr[0]);              // logs 'this is the first element'
console.log(arr[1]);              // logs 'this is the second element'
console.log(arr[arr.length - 1]); // logs 'this is the second element'

Array elements are object properties in the same way that toString is a property, but trying to access an element of an array as follows throws a syntax error, because the property name is not valid:

console.log(arr.0); // a syntax error

There is nothing special about JavaScript arrays and the properties that cause this. JavaScript properties that begin with a digit cannot be referenced with dot notation; and must be accessed using bracket notation. For example, if you had an object with a property named '3d', it can only be referenced using bracket notation. E.g.:

var years = [1950, 1960, 1970, 1980, 1990, 2000, 2010];
console.log(years.0);   // a syntax error
console.log(years[0]);  // works properly

renderer.3d.setTexture(model, 'character.png');     // a syntax error
renderer['3d'].setTexture(model, 'character.png');  // works properly

Note that in the 3d example, '3d' had to be quoted. It's possible to quote the JavaScript array indexes as well (e.g., years['2'] instead of years[2]), although it's not necessary. The 2 in years[2] is coerced into a string by the JavaScript engine through an implicit toString conversion. It is for this reason that '2' and '02' would refer to two different slots on the years object and the following example could be true:

console.log(years['2'] != years['02']);

Similarly, object properties which happen to be reserved words(!) can only be accessed as string literals in bracket notation(but it can be accessed by dot notation in firefox 40.0a2 at least):

var promise = {
  'var'  : 'text',
  'array': [1, 2, 3, 4]
};

console.log(promise['array']);

Relationship between `length` and numerical properties

A JavaScript array's {{jsxref("Array.length", "length")}} property and numerical properties are connected. Several of the built-in array methods (e.g., {{jsxref("Array.join", "join")}}, {{jsxref("Array.slice", "slice")}}, {{jsxref("Array.indexOf", "indexOf")}}, etc.) take into account the value of an array's {{jsxref("Array.length", "length")}} property when they're called. Other methods (e.g., {{jsxref("Array.push", "push")}}, {{jsxref("Array.splice", "splice")}}, etc.) also result in updates to an array's {{jsxref("Array.length", "length")}} property.

var fruits = [];
fruits.push('banana', 'apple', 'peach');

console.log(fruits.length); // 3

When setting a property on a JavaScript array when the property is a valid array index and that index is outside the current bounds of the array, the engine will update the array's {{jsxref("Array.length", "length")}} property accordingly:

fruits[5] = 'mango';
console.log(fruits[5]); // 'mango'
console.log(Object.keys(fruits));  // ['0', '1', '2', '5']
console.log(fruits.length); // 6

Increasing the {{jsxref("Array.length", "length")}}.

fruits.length = 10;
console.log(Object.keys(fruits)); // ['0', '1', '2', '5']
console.log(fruits.length); // 10

Decreasing the {{jsxref("Array.length", "length")}} property does, however, delete elements.

fruits.length = 2;
console.log(Object.keys(fruits)); // ['0', '1']
console.log(fruits.length); // 2

This is explained further on the {{jsxref("Array.length")}} page.

Creating an array using the result of a match

The result of a match between a regular expression and a string can create a JavaScript array. This array has properties and elements which provide information about the match. Such an array is returned by {{jsxref("RegExp.exec")}}, {{jsxref("String.match")}}, and {{jsxref("String.replace")}}. To help explain these properties and elements, look at the following example and then refer to the table below:

// Match one d followed by one or more b's followed by one d
// Remember matched b's and the following d
// Ignore case

var myRe = /d(b+)(d)/i;
var myArray = myRe.exec('cdbBdbsbz');

The properties and elements returned from this match are as follows:

Property/Element	Description	Example
`input`	A read-only property that reflects the original string against which the regular expression was matched.	cdbBdbsbz
`index`	A read-only property that is the zero-based index of the match in the string.	1
`[0]`	A read-only element that specifies the last matched characters.	dbBd
`[1], ...[n]`	Read-only elements that specify the parenthesized substring matches, if included in the regular expression. The number of possible parenthesized substrings is unlimited.	[1]: bB [2]: d

Properties

Array.length: The Array constructor's length property whose value is 1.
{{jsxref("Array.@@species", "get Array[@@species]")}}: The constructor function that is used to create derived objects.
{{jsxref("Array.prototype")}}: Allows the addition of properties to all array objects.

Methods

{{jsxref("Array.from()")}}: Creates a new Array instance from an array-like or iterable object.
{{jsxref("Array.isArray()")}}: Returns true if a variable is an array, if not false.
{{jsxref("Array.of()")}}: Creates a new Array instance with a variable number of arguments, regardless of number or type of the arguments.

`Array` instances

All Array instances inherit from {{jsxref("Array.prototype")}}. The prototype object of the Array constructor can be modified to affect all Array instances.

Properties

{{page('/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/prototype', 'Properties')}}

Methods

Mutator methods

{{page('en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/prototype', 'Mutator_methods')}}

Accessor methods

{{page('en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/prototype', 'Accessor_methods')}}

Iteration methods

{{page('en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/prototype', 'Iteration_methods')}}

`Array` generic methods

Array generics are non-standard, deprecated and will get removed near future. Note that you can not rely on them cross-browser. However, there is a shim available on GitHub.

Sometimes you would like to apply array methods to strings or other array-like objects (such as function {{jsxref("Functions/arguments", "arguments", "", 1)}}). By doing this, you treat a string as an array of characters (or otherwise treat a non-array as an array). For example, in order to check that every character in the variable str is a letter, you would write:

function isLetter(character) {
  return character >= 'a' && character <= 'z';
}

if (Array.prototype.every.call(str, isLetter)) {
  console.log("The string '" + str + "' contains only letters!");
}

This notation is rather wasteful and JavaScript 1.6 introduced a generic shorthand:

if (Array.every(str, isLetter)) {
  console.log("The string '" + str + "' contains only letters!");
}

{{jsxref("Global_Objects/String", "Generics", "#String_generic_methods", 1)}} are also available on {{jsxref("String")}}.

These are not part of ECMAScript standards (though the ES2015 {{jsxref("Array.from()")}} can be used to achieve this). The following is a shim to allow its use in all browsers:

// Assumes Array extras already present (one may use polyfills for these as well)
(function() {
  'use strict';

  var i,
    // We could also build the array of methods with the following, but the
    //   getOwnPropertyNames() method is non-shimable:
    // Object.getOwnPropertyNames(Array).filter(function(methodName) {
    //   return typeof Array[methodName] === 'function'
    // });
    methods = [
      'join', 'reverse', 'sort', 'push', 'pop', 'shift', 'unshift',
      'splice', 'concat', 'slice', 'indexOf', 'lastIndexOf',
      'forEach', 'map', 'reduce', 'reduceRight', 'filter',
      'some', 'every', 'find', 'findIndex', 'entries', 'keys',
      'values', 'copyWithin', 'includes'
    ],
    methodCount = methods.length,
    assignArrayGeneric = function(methodName) {
      if (!Array[methodName]) {
        var method = Array.prototype[methodName];
        if (typeof method === 'function') {
          Array[methodName] = function() {
            return method.call.apply(method, arguments);
          };
        }
      }
    };

  for (i = 0; i < methodCount; i++) {
    assignArrayGeneric(methods[i]);
  }
}());

דוגמאות

Creating an array

The following example creates an array, msgArray, with a length of 0, then assigns values to msgArray[0] and msgArray[99], changing the length of the array to 100.

var msgArray = [];
msgArray[0] = 'Hello';
msgArray[99] = 'world';

if (msgArray.length === 100) {
  console.log('The length is 100.');
}

Creating a two-dimensional array

The following creates a chess board as a two dimensional array of strings. The first move is made by copying the 'p' in (6,4) to (4,4). The old position (6,4) is made blank.

var board = [
  ['R','N','B','Q','K','B','N','R'],
  ['P','P','P','P','P','P','P','P'],
  [' ',' ',' ',' ',' ',' ',' ',' '],
  [' ',' ',' ',' ',' ',' ',' ',' '],
  [' ',' ',' ',' ',' ',' ',' ',' '],
  [' ',' ',' ',' ',' ',' ',' ',' '],
  ['p','p','p','p','p','p','p','p'],
  ['r','n','b','q','k','b','n','r'] ];

console.log(board.join('\n') + '\n\n');

// Move King's Pawn forward 2
board[4][4] = board[6][4];
board[6][4] = ' ';
console.log(board.join('\n'));

Here is the output:

R,N,B,Q,K,B,N,R
P,P,P,P,P,P,P,P
 , , , , , , ,
 , , , , , , ,
 , , , , , , ,
 , , , , , , ,
p,p,p,p,p,p,p,p
r,n,b,q,k,b,n,r

R,N,B,Q,K,B,N,R
P,P,P,P,P,P,P,P
 , , , , , , ,
 , , , , , , ,
 , , , ,p, , ,
 , , , , , , ,
p,p,p,p, ,p,p,p
r,n,b,q,k,b,n,r

Specifications

Specification	Status	Comment
{{SpecName('ES1')}}	{{Spec2('ES1')}}	Initial definition.
{{SpecName('ES5.1', '#sec-15.4', 'Array')}}	{{Spec2('ES5.1')}}	New methods added: {{jsxref("Array.isArray")}}, {{jsxref("Array.prototype.indexOf", "indexOf")}}, {{jsxref("Array.prototype.lastIndexOf", "lastIndexOf")}}, {{jsxref("Array.prototype.every", "every")}}, {{jsxref("Array.prototype.some", "some")}}, {{jsxref("Array.prototype.forEach", "forEach")}}, {{jsxref("Array.prototype.map", "map")}}, {{jsxref("Array.prototype.filter", "filter")}}, {{jsxref("Array.prototype.reduce", "reduce")}}, {{jsxref("Array.prototype.reduceRight", "reduceRight")}}
{{SpecName('ES2015', '#sec-array-objects', 'Array')}}	{{Spec2('ES2015')}}	New methods added: {{jsxref("Array.from")}}, {{jsxref("Array.of")}}, {{jsxref("Array.prototype.find", "find")}}, {{jsxref("Array.prototype.findIndex", "findIndex")}}, {{jsxref("Array.prototype.fill", "fill")}}, {{jsxref("Array.prototype.copyWithin", "copyWithin")}}
{{SpecName('ESDraft', '#sec-array-objects', 'Array')}}	{{Spec2('ESDraft')}}	New method added: {{jsxref("Array.prototype.includes()")}}

Browser compatibility

Feature	Chrome	Firefox (Gecko)	Internet Explorer	Opera	Safari
Basic support	{{CompatVersionUnknown}}	{{CompatVersionUnknown}}	{{CompatVersionUnknown}}	{{CompatVersionUnknown}}	{{CompatVersionUnknown}}

Feature	Android	Chrome for Android	Firefox Mobile (Gecko)	IE Mobile	Opera Mobile	Safari Mobile
Basic support	{{CompatVersionUnknown}}	{{CompatVersionUnknown}}	{{CompatVersionUnknown}}	{{CompatVersionUnknown}}	{{CompatVersionUnknown}}	{{CompatVersionUnknown}}

תחביר

פרמטרים

Description

גישה לאלמנטים שבמערך

Relationship between length and numerical properties

Creating an array using the result of a match

Properties

Methods

Array instances

Properties

Methods

Mutator methods

Accessor methods

Iteration methods

Array generic methods

דוגמאות

Creating an array

Creating a two-dimensional array

Specifications

Browser compatibility

ראה גם

Relationship between `length` and numerical properties

`Array` instances

`Array` generic methods