> For the complete documentation index, see [llms.txt](https://lodash.shujuwajue.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://lodash.shujuwajue.com/array/indexof.md).

# \_.indexOf（获取元素的索引值）

**语法：**

```javascript
_.indexOf(array, value, [fromIndex=0])
```

**源代码链接：**[source](https://github.com/lodash/lodash/blob/4.17.10/lodash.js#L7450)

**npm包链接：**[npm package](https://www.npmjs.com/package/lodash.indexof)

**描述：**

使用[`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)等值比较，返回首次`value`在数组`array`中被找到的 索引值， 如果`fromIndex`为负值，将从数组`array`尾端索引进行匹配。

**开始版本：**0.1.0

**参数：**

* `array (Array)`: 需要查找的数组。
* `value (*)`: 需要查找的值。
* `[fromIndex=0] (number)`: 开始查询的位置。

**返回值：**

* `(number):` 返回 值value在数组中的索引位置, 没有找到为返回-1。

**例子：**

```javascript
_.indexOf([1, 2, 1, 2], 2);
// => 1

// Search from the `fromIndex`.
_.indexOf([1, 2, 1, 2], 2, 2);
// => 3
```


---

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