blocks|key|336747|text|数组文字表示法是仅使用空方括号定义新数组的地方。在您的示例中：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|336748|var+myArray+=+[];|code-block|syntax|javascript|336749|这是一种定义数组的“新”方式，我认为它更短/更简洁。|336750|下面的示例解释了它们之间的区别：|336751|var+a+=+[],++++++++++++//+these+are+the+same
++++b+=+new+Array(),+++//+a+and+b+are+arrays+with+length+0

++++c+=+['foo',+'bar'],+++++++++++//+these+are+the+same
++++d+=+new+Array('foo',+'bar'),++//+c+and+d+are+arrays+with+2+strings

++++//+these+are+different:
++++e+=+[3],+++++++++++++//+e.length+==+1,+e[0]+==+3
++++f+=+new+Array(3);+++//+f.length+==+3,+f[0]+==+undefined|336752|336753|+Reference：What’s+the+difference+between+“Array()”+and+“[]”+while+declaring+a+JavaScript+array?|blockquote|offset|length|style|BOLD|336754|336755|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/a/931875/177125^0|0|0|0|0|0|0|1|9|B|2C|0|0|0^^$0|@$1|2|3|4|5|6|7|13|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|14|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|15|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|16|8|@]|9|@]|A|$]]|$1|K|3|L|5|D|7|17|8|@]|9|@]|A|$E|F]]|$1|M|3|-4|5|6|7|18|8|@]|9|@]|A|$]]|$1|N|3|O|5|P|7|19|8|@$Q|1A|R|1B|S|T]]|9|@$Q|1C|R|1D|1|1E]]|A|$]]|$1|U|3|-4|5|6|7|1F|8|@]|9|@]|A|$]]|$1|V|3|-4|5|6|7|1G|8|@]|9|@]|A|$]]]|W|$X|$5|Y|Z|10|A|$11|12]]]]

array literal notation is where you define a new array using just empty brackets. In your example:

<pre><code>var myArray = [];
</code></pre>

It is the "new" way of defining arrays, and I suppose it is shorter/cleaner.

The examples below explain the difference between them:

<pre><code>var a = [], // these are the same
 b = new Array(), // a and b are arrays with length 0

 c = ['foo', 'bar'], // these are the same
 d = new Array('foo', 'bar'), // c and d are arrays with 2 strings

 // these are different:
 e = [3], // e.length == 1, e[0] == 3
 f = new Array(3); // f.length == 3, f[0] == undefined
</code></pre>

<blockquote>
 Reference: <a href="https://stackoverflow.com/a/931875/177125">What’s the difference between “Array()” and “[]” while declaring a JavaScript array?</a>
</blockquote>

blocks|key|337738|text|另请参阅：What’s+wrong+with+var+x+=+new+Array();|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|337739|除了克罗克福德的论点之外，我认为这也是因为其他语言也有类似的数据结构，恰好使用相同的语法；例如，Python+has+lists+and+dictionaries；请参见以下示例：|337740|//+this+is+a+Python+list
a+=+[66.25,+333,+333,+1,+1234.5]

//+this+is+a+Python+dictionary
tel+=+{'jack':+4098,+'sape':+4139}|code-block|syntax|javascript|337741|Python在语法上也是正确的Javascript，这不是很好吗？(是的，结尾的分号丢失了，但Javascript也不需要这些分号)|337742|因此，通过在编程中重用常见的范例，我们使每个人不必重新学习不应该学习的东西。|337743|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/questions/885156/whats-wrong-with-var-x-new-array|1|http://docs.python.org/tutorial/datastructures.html^0|5|12|0|0|1C|X|1|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Y|8|@]|9|@$A|Z|B|10|1|11]]|C|$]]|$1|D|3|E|5|6|7|12|8|@]|9|@$A|13|B|14|1|15]]|C|$]]|$1|F|3|G|5|H|7|16|8|@]|9|@]|C|$I|J]]|$1|K|3|L|5|6|7|17|8|@]|9|@]|C|$]]|$1|M|3|N|5|6|7|18|8|@]|9|@]|C|$]]|$1|O|3|-4|5|6|7|19|8|@]|9|@]|C|$]]]|P|$Q|$5|R|S|T|C|$U|V]]|W|$5|R|S|T|C|$U|X]]]]

See also: <a href="https://stackoverflow.com/questions/885156/whats-wrong-with-var-x-new-array">What’s wrong with var x = new Array();</a>

Aside from the Crockford argument, I believe it is also due to the fact that other languages have similar data structures that happen to use the same syntax; for example, <a href="http://docs.python.org/tutorial/datastructures.html" rel="nofollow noreferrer">Python has lists and dictionaries</a>; see the following examples:

<pre><code>// this is a Python list
a = [66.25, 333, 333, 1, 1234.5]

// this is a Python dictionary
tel = {'jack': 4098, 'sape': 4139}
</code></pre>

Isn't it neat how Python is also grammatically correct Javascript? (yes, the ending semi-colons are missing, but those aren't required for Javascript, either)

Thus, by reusing common paradigms in programming, we save everyone from having to relearn something that shouldn't have to.

blocks|key|340243|text|除了克罗克福德的论点，jsPerf说它更快。http://jsperf.com/new-vs-literal-array-declaration|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|340244|entityMap|0|LINK|mutability|MUTABLE|url|http://jsperf.com/new-vs-literal-array-declaration^0|M|1E|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

Aside from the Crockford argument, jsPerf says that it's faster. <a href="http://jsperf.com/new-vs-literal-array-declaration" rel="nofollow">http://jsperf.com/new-vs-literal-array-declaration</a>

blocks|key|3316327|text|在查看了@ecMode+jsperf之后，我做了一些进一步的测试。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3316328|当使用推送添加到数组时，在Chrome上new+Array()的速度要快得多：|3316329|http://jsperf.com/new-vs-literal-array-declaration/2|offset|length|3316330|对于[]来说，使用index来添加会稍微快一点。|3316331|entityMap|0|LINK|mutability|MUTABLE|url^0|0|0|0|1G|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|R|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|S|8|@]|9|@$F|T|G|U|1|V]]|A|$]]|$1|H|3|I|5|6|7|W|8|@]|9|@]|A|$]]|$1|J|3|-4|5|6|7|X|8|@]|9|@]|A|$]]]|K|$L|$5|M|N|O|A|$P|E]]]]

After looking at @ecMode jsperf, I did some further tests.

When using push to add to the array new Array() is considerably faster on Chrome:

<a href="http://jsperf.com/new-vs-literal-array-declaration/2" rel="nofollow">http://jsperf.com/new-vs-literal-array-declaration/2</a>

Using index to add is slightly faster for [].

JSLint is giving me this error:

<blockquote>
 Problem at line 11 character 33: Use the array literal notation [].
</blockquote>

<pre><code>var myArray = new Array();
</code></pre>

What is array literal notation and why does it want me to use it instead?

It shows here that <code>new Array();</code> should work fine... is there something I'm missing?

What is array literal notation in javascript and when should you use it?

数据结构

Python

JSLint给了我这个错误：第11行字符33处的问题:使用数组文字表示法[]。var myArray = new Array();什么是数组文字表示法?为什么它要我用它来代替？这里显示了new Array();应该可以很好地工作。我是不是漏掉了什么？

问什么是javascript中的数组文字表示法，什么时候应该使用它？
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