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diff --git a/files/pt-pt/web/javascript/reference/global_objects/array/index.html b/files/pt-pt/web/javascript/reference/global_objects/array/index.html deleted file mode 100644 index 5f26f41549..0000000000 --- a/files/pt-pt/web/javascript/reference/global_objects/array/index.html +++ /dev/null @@ -1,440 +0,0 @@ ---- -title: Array -slug: Web/JavaScript/Reference/Global_Objects/Array -tags: - - Array - - Class - - Exemplo - - Global Objects - - JavaScript - - Referencia - - 'l10n:priority' -translation_of: Web/JavaScript/Reference/Global_Objects/Array ---- -<div>{{JSRef}}</div> - -<p>A classe de JavaScript <strong><code>Array</code></strong> é um objecto global que é utilizado na construção de matrizes; que são objectos de alto nível, semelhantes a listas.</p> - -<h2 id="Descrição">Descrição</h2> - -<p>Arrays são objectos em forma de lista, cujo protótipo tem métodos para realizar operações de travessia e mutação. Nem o comprimento de uma array JavaScript nem os tipos dos seus elementos são fixos. Uma vez que o comprimento de uma array pode mudar a qualquer momento, e os dados podem ser armazenados em locais não contíguos da array, não é garantido que uma array JavaScript seja densa; isto depende de como o programador opta por usá-las. Em geral, estas são características convenientes; mas se estas características não forem desejáveis para seu uso particular, você pode considerar o uso de arrays tipadas.</p> - -<p>Uma array não pode utilizar strings como índices de elementos (como num {{InterWiki("wikipedia", "Vetor_associativo", "array associativa")}}), deve utilizar números inteiros. A definição ou acesso através de não-inteiros usando notação de parênteses (ou notação de pontos) não definirá ou recuperará um elemento da própria lista da array, mas definirá ou acessará uma variável associada à <a href="pt-PT/docs/Web/JavaScript/Estruturas_de_dados#Objetos">coleção de propriedades dessa array</a>. As propriedades da array e a lista de elementos do mesmo são separadas, e as operações de translação e mutação da array não podem ser aplicadas a essas propriedades com nome.</p> - -<p><strong>Criar uma Array</strong></p> - -<pre class="brush: js notranslate">var fruits = ['Apple', 'Banana']; - -console.log(fruits.length); -// 2 -</pre> - -<p><strong>Aceder (através de índice) item<span class="original-content"> da </span>Array</strong></p> - -<pre class="brush: js notranslate">var first = fruits[0]; -// Apple - -var last = fruits[fruits.length - 1]; -// Banana -</pre> - -<p><strong>Loop over an Array</strong></p> - -<pre class="brush: js notranslate">fruits.forEach(function(item, index, array) { - console.log(item, index); -}); -// Apple 0 -// Banana 1 -</pre> - -<p><strong>Adicionar um item ao fim da Array</strong></p> - -<pre class="brush: js notranslate">var newLength = fruits.push('Orange'); -// ["Apple", "Banana", "Orange"] -</pre> - -<p><strong>Remover um item do fim da Array</strong></p> - -<pre class="brush: js notranslate">var last = fruits.pop(); // remove Orange (from the end) -// ["Apple", "Banana"]; -</pre> - -<p><strong>Remover um item do início da Array</strong></p> - -<pre class="brush: js notranslate">var first = fruits.shift(); // remove Apple from the front -// ["Banana"]; -</pre> - -<p><strong>Ad</strong><strong>icionar um item ao início da Array</strong></p> - -<pre class="brush: js notranslate">var newLength = fruits.unshift('Strawberry') // add to the front -// ["Strawberry", "Banana"]; -</pre> - -<p><strong>Encontrar o índice dum item na Array</strong></p> - -<pre class="brush: js notranslate">fruits.push('Mango'); -// ["Strawberry", "Banana", "Mango"] - -var pos = fruits.indexOf('Banana'); -// 1 -</pre> - -<p><strong>Remover um item pela posição do índice</strong></p> - -<pre class="brush: js notranslate">var removedItem = fruits.splice(pos, 1); // this is how to remove an item - -// ["Strawberry", "Mango"]</pre> - -<p><strong>Remover items pela posição do índice</strong></p> - -<pre class="brush: js notranslate">var vegetables = ['Cabbage', 'Turnip', 'Radish', 'Carrot']; -console.log(vegetables); -// ["Cabbage", "Turnip", "Radish", "Carrot"] - -var pos = 1, n = 2; - -var removedItems = vegetables.splice(pos, n); -// this is how to remove items, n defines the number of items to be removed, -// from that position(pos) onward to the end of array. - -console.log(vegetables); -// ["Cabbage", "Carrot"] (the original array is changed) - -console.log(removedItems); -// ["Turnip", "Radish"]</pre> - -<p><strong>Copiar uma Array</strong></p> - -<pre class="brush: js notranslate">var shallowCopy = fruits.slice(); // this is how to make a copy -// ["Strawberry"] -</pre> - -<h3 id="Como_aceder_a_elementos_da_array">Como aceder a elementos da array</h3> - -<p>JavaScript arrays are zero-indexed: the first element of an array is at index <code>0</code>, and the last element is at the index equal to the value of the array's {{jsxref("Array.length", "length")}} property minus 1.</p> - -<pre class="brush: js notranslate">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' -</pre> - -<p>Array elements are object properties in the same way that <code>toString</code> 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:</p> - -<pre class="brush: js notranslate">console.log(arr.0); // a syntax error -</pre> - -<p>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 <code>'3d'</code>, it can only be referenced using bracket notation. E.g.:</p> - -<pre class="brush: js notranslate">var years = [1950, 1960, 1970, 1980, 1990, 2000, 2010]; -console.log(years.0); // a syntax error -console.log(years[0]); // works properly -</pre> - -<pre class="brush: js notranslate">renderer.3d.setTexture(model, 'character.png'); // a syntax error -renderer['3d'].setTexture(model, 'character.png'); // works properly -</pre> - -<p>Note that in the <code>3d</code> example, <code>'3d'</code> had to be quoted. It's possible to quote the JavaScript array indexes as well (e.g., <code>years['2']</code> instead of <code>years[2]</code>), although it's not necessary. The 2 in <code>years[2]</code> is coerced into a string by the JavaScript engine through an implicit <code>toString</code> conversion. It is for this reason that <code>'2'</code> and <code>'02'</code> would refer to two different slots on the <code>years</code> object and the following example could be <code>true</code>:</p> - -<pre class="brush: js notranslate">console.log(years['2'] != years['02']); -</pre> - -<p>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):</p> - -<pre class="brush: js notranslate">var promise = { - 'var' : 'text', - 'array': [1, 2, 3, 4] -}; - -console.log(promise['var']); -</pre> - -<h3 id="Relationship_between_length_and_numerical_properties">Relationship between <code>length</code> and numerical properties</h3> - -<p>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.</p> - -<pre class="brush: js notranslate">var fruits = []; -fruits.push('banana', 'apple', 'peach'); - -console.log(fruits.length); // 3 -</pre> - -<p>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:</p> - -<pre class="brush: js notranslate">fruits[5] = 'mango'; -console.log(fruits[5]); // 'mango' -console.log(Object.keys(fruits)); // ['0', '1', '2', '5'] -console.log(fruits.length); // 6 -</pre> - -<p>Increasing the {{jsxref("Array.length", "length")}}.</p> - -<pre class="brush: js notranslate">fruits.length = 10; -console.log(Object.keys(fruits)); // ['0', '1', '2', '5'] -console.log(fruits.length); // 10 -</pre> - -<p>Decreasing the {{jsxref("Array.length", "length")}} property does, however, delete elements.</p> - -<pre class="brush: js notranslate">fruits.length = 2; -console.log(Object.keys(fruits)); // ['0', '1'] -console.log(fruits.length); // 2 -</pre> - -<p>This is explained further on the {{jsxref("Array.length")}} page.</p> - -<h3 id="Creating_an_array_using_the_result_of_a_match">Creating an array using the result of a match</h3> - -<p>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:</p> - -<pre class="brush: js notranslate">// 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'); -</pre> - -<p>The properties and elements returned from this match are as follows:</p> - -<table class="fullwidth-table"> - <tbody> - <tr> - <td class="header">Property/Element</td> - <td class="header">Description</td> - <td class="header">Example</td> - </tr> - <tr> - <td><code>input</code></td> - <td>A read-only property that reflects the original string against which the regular expression was matched.</td> - <td>cdbBdbsbz</td> - </tr> - <tr> - <td><code>index</code></td> - <td>A read-only property that is the zero-based index of the match in the string.</td> - <td>1</td> - </tr> - <tr> - <td><code>[0]</code></td> - <td>A read-only element that specifies the last matched characters.</td> - <td>dbBd</td> - </tr> - <tr> - <td><code>[1], ...[n]</code></td> - <td>Read-only elements that specify the parenthesized substring matches, if included in the regular expression. The number of possible parenthesized substrings is unlimited.</td> - <td>[1]: bB<br> - [2]: d</td> - </tr> - </tbody> -</table> - -<h2 id="Properties">Properties</h2> - -<dl> - <dt><code>Array.length</code></dt> - <dd>The <code>Array</code> constructor's length property whose value is 1.</dd> - <dt>{{jsxref("Array.@@species", "get Array[@@species]")}}</dt> - <dd>The constructor function that is used to create derived objects.</dd> - <dt>{{jsxref("Array.prototype")}}</dt> - <dd>Allows the addition of properties to all array objects.</dd> -</dl> - -<h2 id="Methods">Methods</h2> - -<dl> - <dt>{{jsxref("Array.from()")}}</dt> - <dd>Creates a new <code>Array</code> instance from an array-like or iterable object.</dd> - <dt>{{jsxref("Array.isArray()")}}</dt> - <dd>Returns true if a variable is an array, if not false.</dd> - <dt>{{jsxref("Array.of()")}}</dt> - <dd>Creates a new <code>Array</code> instance with a variable number of arguments, regardless of number or type of the arguments.</dd> -</dl> - -<h2 id="Array_instances"><code>Array</code> instances</h2> - -<p>All <code>Array</code> instances inherit from {{jsxref("Array.prototype")}}. The prototype object of the <code>Array</code> constructor can be modified to affect all <code>Array</code> instances.</p> - -<h3 id="Properties_2">Properties</h3> - -<div>{{page('/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/prototype', 'Properties')}}</div> - -<h3 id="Methods_2">Methods</h3> - -<h4 id="Mutator_methods">Mutator methods</h4> - -<div>{{page('en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/prototype', 'Mutator_methods')}}</div> - -<h4 id="Accessor_methods">Accessor methods</h4> - -<div>{{page('en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/prototype', 'Accessor_methods')}}</div> - -<h4 id="Iteration_methods">Iteration methods</h4> - -<div>{{page('en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/prototype', 'Iteration_methods')}}</div> - -<h2 id="Array_generic_methods"><code>Array</code> generic methods</h2> - -<div class="warning"> -<p><strong>Array generics are non-standard, deprecated and will get removed in the near future</strong>. </p> -</div> - -<p>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 <var>str</var> is a letter, you would write:</p> - -<pre class="brush: js notranslate">function isLetter(character) { - return character >= 'a' && character <= 'z'; -} - -if (Array.prototype.every.call(str, isLetter)) { - console.log("The string '" + str + "' contains only letters!"); -} -</pre> - -<p>This notation is rather wasteful and JavaScript 1.6 introduced a generic shorthand:</p> - -<pre class="brush: js notranslate">if (Array.every(str, isLetter)) { - console.log("The string '" + str + "' contains only letters!"); -} -</pre> - -<p>{{jsxref("Global_Objects/String", "Generics", "#String_generic_methods", 1)}} are also available on {{jsxref("String")}}.</p> - -<p>These are <strong>not</strong> part of ECMAScript standards and they are not supported by non-Gecko browsers. As a standard alternative, you can convert your object to a proper array using {{jsxref("Array.from()")}}; although that method may not be supported in old browsers:</p> - -<pre class="brush: js notranslate">if (Array.from(str).every(isLetter)) { - console.log("The string '" + str + "' contains only letters!"); -} -</pre> - -<h2 id="Examples">Examples</h2> - -<h3 id="Creating_an_array">Creating an array</h3> - -<p>The following example creates an array, <code>msgArray</code>, with a length of 0, then assigns values to <code>msgArray[0]</code> and <code>msgArray[99]</code>, changing the length of the array to 100.</p> - -<pre class="brush: js notranslate">var msgArray = []; -msgArray[0] = 'Hello'; -msgArray[99] = 'world'; - -if (msgArray.length === 100) { - console.log('The length is 100.'); -} -</pre> - -<h3 id="Creating_a_two-dimensional_array">Creating a two-dimensional array</h3> - -<p>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.</p> - -<pre class="brush: js notranslate">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')); -</pre> - -<p>Here is the output:</p> - -<pre class="eval notranslate">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 -</pre> - -<h3 id="Using_an_array_to_tabulate_a_set_of_values">Using an array to tabulate a set of values</h3> - -<pre class="brush: js notranslate">values = []; -for (var x = 0; x < 10; x++){ - values.push([ - 2 ** x, - 2 * x ** 2 - ]) -}; -console.table(values)</pre> - -<p>Results in</p> - -<pre class="eval notranslate">0 1 0 -1 2 2 -2 4 8 -3 8 18 -4 16 32 -5 32 50 -6 64 72 -7 128 98 -8 256 128 -9 512 162</pre> - -<p>(First column is the (index))</p> - -<h2 id="Specifications">Specifications</h2> - -<table class="standard-table"> - <tbody> - <tr> - <th scope="col">Specification</th> - <th scope="col">Status</th> - <th scope="col">Comment</th> - </tr> - <tr> - <td>{{SpecName('ES1')}}</td> - <td>{{Spec2('ES1')}}</td> - <td>Initial definition.</td> - </tr> - <tr> - <td>{{SpecName('ES5.1', '#sec-15.4', 'Array')}}</td> - <td>{{Spec2('ES5.1')}}</td> - <td>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")}}</td> - </tr> - <tr> - <td>{{SpecName('ES6', '#sec-array-objects', 'Array')}}</td> - <td>{{Spec2('ES6')}}</td> - <td>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")}}</td> - </tr> - <tr> - <td>{{SpecName('ESDraft', '#sec-array-objects', 'Array')}}</td> - <td>{{Spec2('ESDraft')}}</td> - <td>New method added: {{jsxref("Array.prototype.includes()")}}</td> - </tr> - </tbody> -</table> - -<h2 id="Compatibilidade_de_Navegadores">Compatibilidade de Navegadores</h2> - -<div class="hidden">A tabela de compatibilidade nesta página é gerada a partir de dados estruturados. Se quiser contribuir para os dados, por favor consulte <a href="https://github.com/mdn/browser-compat-data">https://github.com/mdn/browser-compat-data</a> e envie-nos um pull request.</div> - -<p>{{Compat("javascript.builtins.Array")}}</p> - -<h2 id="See_also">See also</h2> - -<ul> - <li><a href="/en-US/docs/Web/JavaScript/Guide/Working_with_Objects#Indexing_object_properties">JavaScript Guide: “Indexing object properties”</a></li> - <li><a href="/en-US/docs/Web/JavaScript/Guide/Predefined_Core_Objects#Array_Object">JavaScript Guide: “Predefined Core Objects: <code>Array</code> Object”</a></li> - <li><a href="/en-US/docs/Web/JavaScript/Reference/Operators/Array_comprehensions">Array comprehensions</a></li> - <li><a href="https://github.com/plusdude/array-generics">Polyfill for JavaScript 1.8.5 Array Generics and ECMAScript 5 Array Extras</a></li> - <li><a href="/en-US/docs/JavaScript_typed_arrays">Typed Arrays</a></li> -</ul> |