blocks|key|4183371|text|"splice()“函数返回的不是受影响的数组，而是已删除元素的数组。如果不删除任何内容，则结果数组为空。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4183372|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

The "splice()" function returns not the affected array, but the array of removed elements. If you remove nothing, the result array is empty.

blocks|key|517260|text|array.splice函数拼接一个数组，返回被删除的元素。由于您没有删除任何内容，而只是使用它来插入一个元素，因此它将返回空数组。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|BOLD|entityRanges|data|517261|我想这就是你想要的。|517262|var+a+=+[1,2,3,4,5];+
a.splice(1,+0,+'foo');+
var+b+=+a;
console.log(b);+|code-block|syntax|javascript|517263|entityMap^0|0|C|L|3|0|0|0^^$0|@$1|2|3|4|5|6|7|P|8|@$9|Q|A|R|B|C]|$9|S|A|T|B|D]]|E|@]|F|$]]|$1|G|3|H|5|6|7|U|8|@]|E|@]|F|$]]|$1|I|3|J|5|K|7|V|8|@]|E|@]|F|$L|M]]|$1|N|3|-4|5|6|7|W|8|@]|E|@]|F|$]]]|O|$]]

The <code>array.splice</code> function splices an array returns the elements that were removed. Since you are not removing anything and just using it to insert an element, it will return the empty array.

I think this is what you are wanting.

<pre><code>var a = [1,2,3,4,5]; 
a.splice(1, 0, 'foo'); 
var b = a;
console.log(b); 
</code></pre>

blocks|key|4183432|text|splice()修改源数组并返回已删除项的数组。由于您没有要求删除任何项，因此您将得到一个空数组。它会修改原始数组以插入新项。你有没有看过那是什么？在a中查找您的结果。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|4183433|var+a+=+[1,2,3,4,5];
var+b+=+a.splice(1,+0,+'foo');
console.log(a);+++//+[1,'foo',2,3,4,5]
console.log(b);+++//+[]|code-block|syntax|javascript|4183434|在jsFiddle的派生中，请在此处查看a中的结果：http://jsfiddle.net/jfriend00/9cHre/。|4183435|entityMap|0|LINK|mutability|MUTABLE|url|http://jsfiddle.net/jfriend00/9cHre/^0|0|8|23|1|0|0|K|1|Q|10|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@$9|V|A|W|B|C]|$9|X|A|Y|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|Z|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|10|8|@$9|11|A|12|B|C]]|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]]]]

<code>splice()</code> modifies the source array and returns an array of the removed items. Since you didn't ask to remove any items, you get an empty array back. It modifies the original array to insert your new items. Did you look in a to see what it was? Look for your result in <code>a</code>.

<pre><code>var a = [1,2,3,4,5];
var b = a.splice(1, 0, 'foo');
console.log(a); // [1,'foo',2,3,4,5]
console.log(b); // []
</code></pre>

In a derivation of your jsFiddle, see the result in <code>a</code> here: <a href="http://jsfiddle.net/jfriend00/9cHre/" rel="noreferrer">http://jsfiddle.net/jfriend00/9cHre/</a>.

blocks|key|4467868|text|我有这个问题。“splice()方法通过移除或替换现有元素和/或就地添加新元素来更改数组的内容。”https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/splice|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|4467869|这将会起作用：|4467870|var+a+=+[1,2,3,4,5];
a.splice(1,0,'Foo');
console.log(a);|code-block|syntax|javascript|4467871|如果你想在一个函数中使用它，你可以这样做：|4467872|function+placeInMiddle(arr){
+++++
+++++arr.splice(2,0,+"foo");
++++++return+arr;
++++
}++
placeInMiddle([1,2,6,7])|4467873|Mozilla+developer上的Array.prototype.splice()页面比其他资源更清楚地说明了splice方法是如何工作的，以及如何实现它，下面将对此进行简要描述！|4467874|const+months+=+['Jan',+'March',+'April',+'June'];
months.splice(1,+0,+'Feb');
//+inserts+at+index+1
console.log(months);
//+expected+output:+Array+["Jan",+"Feb",+"March",+"April",+"June"]

months.splice(4,+1,+'May');
//+replaces+1+element+at+index+4
console.log(months);
//+expected+output:+Array+["Jan",+"Feb",+"March",+"April",+"May"]|4467875|entityMap|0|LINK|mutability|MUTABLE|url|https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/splice^0|1D|2L|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|10|8|@]|9|@$A|11|B|12|1|13]]|C|$]]|$1|D|3|E|5|6|7|14|8|@]|9|@]|C|$]]|$1|F|3|G|5|H|7|15|8|@]|9|@]|C|$I|J]]|$1|K|3|L|5|6|7|16|8|@]|9|@]|C|$]]|$1|M|3|N|5|H|7|17|8|@]|9|@]|C|$I|J]]|$1|O|3|P|5|6|7|18|8|@]|9|@]|C|$]]|$1|Q|3|R|5|H|7|19|8|@]|9|@]|C|$I|J]]|$1|S|3|-4|5|6|7|1A|8|@]|9|@]|C|$]]]|T|$U|$5|V|W|X|C|$Y|Z]]]]

I had this issue. &quot;The splice() method changes the contents of an array by removing or replacing existing elements and/or adding new elements in place.&quot; <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/splice" rel="nofollow noreferrer">https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/splice</a>
This will work:
<pre><code>var a = [1,2,3,4,5];
a.splice(1,0,'Foo');
console.log(a);
</code></pre>
If you want it inside a function you could do this:
<pre><code>function placeInMiddle(arr){
 
 arr.splice(2,0, &quot;foo&quot;);
 return arr;
 
} 
placeInMiddle([1,2,6,7])
</code></pre>
Array.prototype.splice() page on Mozilla developer is more clear than other resources about how the splice method works and how it can be implemented, described briefly below!
<pre><code>const months = ['Jan', 'March', 'April', 'June'];
months.splice(1, 0, 'Feb');
// inserts at index 1
console.log(months);
// expected output: Array [&quot;Jan&quot;, &quot;Feb&quot;, &quot;March&quot;, &quot;April&quot;, &quot;June&quot;]

months.splice(4, 1, 'May');
// replaces 1 element at index 4
console.log(months);
// expected output: Array [&quot;Jan&quot;, &quot;Feb&quot;, &quot;March&quot;, &quot;April&quot;, &quot;May&quot;]
</code></pre>

I'm really confused about this.

My understanding was that <code>array.splice(startIndex, deleteLength, insertThing)</code> would insert <code>insertThing</code> into the result of <code>splice()</code> at <code>startIndex</code> and delete <code>deleteLength</code>'s worth of entries? ... so:

<pre><code>var a = [1,2,3,4,5];
var b = a.splice(1, 0, 'foo');
console.log(b);
</code></pre>

Should give me:

<pre><code>[1,'foo',2,3,4,5]
</code></pre>

And

<pre><code>console.log([1,2,3,4,5].splice(2, 0, 'foo'));
</code></pre>

should give me

<pre><code>[1,2,'foo',3,4,5]
</code></pre>

etc.

But for some reason it's giving me just an empty array? Take a look: <a href="http://jsfiddle.net/trolleymusic/STmbp/3/">http://jsfiddle.net/trolleymusic/STmbp/3/</a>

Thanks :)

Confusion with javascript array.splice()

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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我对此真的很困惑。我的理解是，array.splice(startIndex, deleteLength, insertThing)会将insertThing插入到startIndex的splice()结果中，并删除deleteLength的条目价值？…所以：var a = [1,2,3,4,5];var b = a....

问与javascript array.splice()混淆
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