blocks|key|1035983|text|一个简单的解决方案是填充第0项：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1035984|var+map+=+[null,+'January',+'February',+'March'];
'First+month+:+'+%2B+map[1];|code-block|syntax|javascript|1035985|从语义上讲，最好使用对象：|1035986|var+map+=+{1:'January',+2:'February',+3:'March'};
'First+month+:+'+%2B+map[1];|1035987|注意这些键实际上不是整型的，对象键总是字符串。|1035988|另外，我们不能使用点符号来访问。(MDN+-+Property+Accessors)|offset|length|1035989|我会选择第一种解决方案，我认为它不那么令人困惑。|1035990|entityMap|0|LINK|mutability|MUTABLE|url|https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Member_Operators^0|0|0|0|0|0|H|O|0|0|0^^$0|@$1|2|3|4|5|6|7|10|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|11|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|12|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|13|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|14|8|@]|9|@]|A|$]]|$1|M|3|N|5|6|7|15|8|@]|9|@$O|16|P|17|1|18]]|A|$]]|$1|Q|3|R|5|6|7|19|8|@]|9|@]|A|$]]|$1|S|3|-4|5|6|7|1A|8|@]|9|@]|A|$]]]|T|$U|$5|V|W|X|A|$Y|Z]]]]

<p>A simple solution is to fill the zeroth item:</p>

<pre><code>var map = [null, 'January', 'February', 'March'];
'First month : ' + map[1];
</code></pre>

<p><br>
Semantically it would be better to use an object:</p>

<pre><code>var map = {1:'January', 2:'February', 3:'March'};
'First month : ' + map[1];
</code></pre>

<p>Note these keys are not ints actually, object keys are always strings.<br>
Also, we can't use dot notation for accessing. (<a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Member_Operators" rel="noreferrer">MDN - Property Accessors</a>)</p>

<p><br>
I'd choose the first solution, which I think is less confusing.</p>


blocks|key|1251152|text|由于谷歌搜索时也会弹出这个问题，比如"javascript+start+array+at+1“，所以我会给出一个不同的答案：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1251153|可以对数组进行切片。所以你可以得到一个切片版本的数组，如下所示：|1251154|var+someArray+=+[0,+1,+2,+3];

someArray.slice(1);
[1,+2,+3]

someArray.slice(2,+4);
[2,+3]|code-block|syntax|javascript|1251155|来源：https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/Array/slice|offset|length|1251156|entityMap|0|LINK|mutability|MUTABLE|url|https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/Array/slice^0|0|0|0|3|2H|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|V|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|W|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|X|8|@]|9|@$K|Y|L|Z|1|10]]|A|$]]|$1|M|3|-4|5|6|7|11|8|@]|9|@]|A|$]]]|N|$O|$5|P|Q|R|A|$S|T]]]]

<p>Since this question also pops up for a Google search like "javascript start array at 1" I will give a different answer:</p>

<p>Arrays can be sliced. So you can get a sliced version of the Array like this:</p>

<pre><code>var someArray = [0, 1, 2, 3];

someArray.slice(1);
[1, 2, 3]

someArray.slice(2, 4);
[2, 3]
</code></pre>

<p>Source: <a href="https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/Array/slice" rel="noreferrer">https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/Array/slice</a></p>


blocks|key|1251318|text|您可以使用delete删除第一个元素，如下所示：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1251319|​|1251320|let+arr+=+['a','b','c'];
delete+arr[0];

console.log(arr[0]);
console.log(arr[1]);|code-block|syntax|javascript|1251321|1251322|或者根本不去定义它：|1251323|1251324|let+arr+=+[,'b','c'];

console.log(arr[0]);
console.log(arr[1]);|1251325|1251326|如果你想确保你总是得到第一个真实的元素，而不管索引是什么，并且有权访问ES6，你可以使用：|1251327|arr.find(Boolean)|1251328|entityMap|0|LINK|mutability|MUTABLE|url|https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/delete^0|5|6|0|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|13|8|@]|9|@$A|14|B|15|1|16]]|C|$]]|$1|D|3|E|5|6|7|17|8|@]|9|@]|C|$]]|$1|F|3|G|5|H|7|18|8|@]|9|@]|C|$I|J]]|$1|K|3|E|5|6|7|19|8|@]|9|@]|C|$]]|$1|L|3|M|5|6|7|1A|8|@]|9|@]|C|$]]|$1|N|3|E|5|6|7|1B|8|@]|9|@]|C|$]]|$1|O|3|P|5|H|7|1C|8|@]|9|@]|C|$I|J]]|$1|Q|3|E|5|6|7|1D|8|@]|9|@]|C|$]]|$1|R|3|S|5|6|7|1E|8|@]|9|@]|C|$]]|$1|T|3|U|5|H|7|1F|8|@]|9|@]|C|$I|J]]|$1|V|3|-4|5|6|7|1G|8|@]|9|@]|C|$]]]|W|$X|$5|Y|Z|10|C|$11|12]]]]

<p>You could use <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/delete" rel="nofollow noreferrer">delete</a> to remove the first element like so:</p>
<p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
<div class="snippet-code">
<pre class="snippet-code-js lang-js prettyprint-override"><code>let arr = ['a','b','c'];
delete arr[0];

console.log(arr[0]);
console.log(arr[1]);</code></pre>
</div>
</div>
</p>
<p>Or just not define it at all:</p>
<p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
<div class="snippet-code">
<pre class="snippet-code-js lang-js prettyprint-override"><code>let arr = [,'b','c'];

console.log(arr[0]);
console.log(arr[1]);</code></pre>
</div>
</div>
</p>
<p>If you want to make sure that you always get the first truthy element regardless of the index and have access to ES6 you can use:</p>
<pre><code>arr.find(Boolean)
</code></pre>


blocks|key|1036188|text|好吧，根据@cletus的说法，你不能这样做，因为它是一个内置的javascript功能，但如果你仍然想要的话，你可以用稍微不同的方式。你可以从1开始编写你自己的索引相关的数组函数(如reduce，map，forEach)，这不是一项困难的任务，但你仍然会问自己:为什么我需要它？|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1036189|Array.prototype.mapWithIndexOne+=+function(func)+{
++const+initial+=+[]
++for+(let+i+=+1;+i+<+this.length+%2B+1;+i%2B%2B)+{
++++initial.push(func(this[i+-+1],+i))
++}
++return+initial
}

const+array+=+['First',+'Second',+'Third',+'Fourth',+'Fifth']

console.log(array.mapWithIndexOne((element,+index)+=>+`${element}-${index}`))
//+=>+["First-1",+"Second-2",+"Third-3",+"Fourth-4",+"Fifth-5"]|code-block|syntax|javascript|1036190|Codepen：https://codepen.io/anon/pen/rvbNZR?editors=0012|1036191|entityMap|0|LINK|mutability|MUTABLE|url|https://codepen.io/anon/pen/rvbNZR?editors=0012^0|2K|6|2R|3|2V|7|0|0|8|1B|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@$9|V|A|W|B|C]|$9|X|A|Y|B|C]|$9|Z|A|10|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|11|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|12|8|@]|D|@$9|13|A|14|1|15]]|E|$]]|$1|M|3|-4|5|6|7|16|8|@]|D|@]|E|$]]]|N|$O|$5|P|Q|R|E|$S|T]]]]

<p>Okay, according to @cletus you couldn't do that because it's a built-in javascript feature but you could go slightly different way if you still want that. You could write your own index-dependent functions of Array (like <code>reduce</code>, <code>map</code>, <code>forEach</code>) to start with 1. It's not a difficult task but still ask yourself: why do I need that?</p>

<pre><code>Array.prototype.mapWithIndexOne = function(func) {
  const initial = []
  for (let i = 1; i &lt; this.length + 1; i++) {
    initial.push(func(this[i - 1], i))
  }
  return initial
}

const array = ['First', 'Second', 'Third', 'Fourth', 'Fifth']

console.log(array.mapWithIndexOne((element, index) =&gt; `${element}-${index}`))
// =&gt; ["First-1", "Second-2", "Third-3", "Fourth-4", "Fifth-5"]
</code></pre>

<p>Codepen: <a href="https://codepen.io/anon/pen/rvbNZR?editors=0012" rel="nofollow noreferrer">https://codepen.io/anon/pen/rvbNZR?editors=0012</a></p>


blocks|key|1251368|text|只需在前面添加一个null|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1251369|a+=+[1,+2,+3,+4]
a.unshift(null)
a[3]++++//+3|code-block|syntax|javascript|1251370|entityMap^0|9|4|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|P|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|L|$]]

<p>Just prepend a <code>null</code>:</p>
<pre><code>a = [1, 2, 3, 4]
a.unshift(null)
a[3]    // 3
</code></pre>


blocks|key|1036336|text|使用Array.map|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1036337|[,1,2,3].map((v,+i)+=>+%2B%2Bi)|code-block|syntax|javascript|1036338|entityMap^0|2|9|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|P|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|L|$]]

<p>Using <code>Array.map</code></p>
<pre><code>[,1,2,3].map((v, i) =&gt; ++i)
</code></pre>


blocks|key|1036233|text|我遇到了一种情况，我需要数组从索引1开始。我这样做了：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1036234|var+products+=+['bar',+'baz'];

products+=+$.makeArray(products);+//+necessary+to+unshift+a+jQuery+object
products.unshift('foo');+//+add+"foo"+to+the+beginning+of+the+array

$(products).each(function(index)+{
++++if+(index+===+0)+{
++++++++return+true;+//+we+will+skip+"foo"
++++}

++++//+From+now+on+we+can+use+products[index]+starting+from+1

});|code-block|syntax|javascript|1036235|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

<p>I faced a situation where I neeeded the array to start from index 1. Here's what I did:</p>

<pre><code>var products = ['bar', 'baz'];

products = $.makeArray(products); // necessary to unshift a jQuery object
products.unshift('foo'); // add "foo" to the beginning of the array

$(products).each(function(index) {
    if (index === 0) {
        return true; // we will skip "foo"
    }

    // From now on we can use products[index] starting from 1

});
</code></pre>


blocks|key|1036022|text|很简单，只需对经典的Javascript+for循环进行两次更改。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1036023|​|1036024|var+Array+=+['a',+'b',+'c'];

for+(var+i+=+1;+i+<=+Array.length;+i%2B%2B)+{
++//"i"+starts+at+1+and+ends
++//after+it+equals+"length"
++console.log(i);
}|code-block|syntax|javascript|1036025|1036026|entityMap^0|L|3|0|0|0|0^^$0|@$1|2|3|4|5|6|7|P|8|@$9|Q|A|R|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|S|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|T|8|@]|D|@]|E|$K|L]]|$1|M|3|G|5|6|7|U|8|@]|D|@]|E|$]]|$1|N|3|-4|5|6|7|V|8|@]|D|@]|E|$]]]|O|$]]

<p>Simple, just make two changes to the classic Javascript <code>for</code> loop.</p>

<p><div class="snippet" data-lang="js" data-hide="false">
<div class="snippet-code">
<pre class="snippet-code-js lang-js prettyprint-override"><code>var Array = ['a', 'b', 'c'];

for (var i = 1; i &lt;= Array.length; i++) {
  //"i" starts at 1 and ends
  //after it equals "length"
  console.log(i);
}</code></pre>
</div>
</div>
</p>


<p>By default the indexing of every JavaScript array starts from 0. I want to create an array whose indexing starts from 1 instead.</p>

<p>I know, must be very trivial... Thanks for your help.</p>


How to create an array in JavaScript whose indexing starts at 1?

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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默认情况下，每个JavaScript数组的索引从0开始。我想创建一个数组，它的索引从1开始。我知道，一定很琐碎……谢谢你的帮助。

问如何在JavaScript中创建索引从1开始的数组？
EN

回答 8

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问如何在JavaScript中创建索引从1开始的数组？EN

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问如何在JavaScript中创建索引从1开始的数组？
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