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# index(of:in:)

Returns the lowest index within a specified range whose corresponding array value is equal to a given object .

```
func index(of anObject: Any, in range: NSRange) -> Int
```

## Parameters

`anObject`

An object.

`range`

The range of indexes in the array within which to search for `anObject`.

## Return Value

The lowest index within `range` whose corresponding array value is equal to `anObject`. If none of the objects within `range` is equal to `anObject`, returns `NSNotFound`.

## Discussion

Starting at `range.location`, each element of the array is passed as an argument to an <doc://com.apple.documentation/documentation/ObjectiveC/NSObjectProtocol/isEqual(_:)> message sent to `anObject` until a match is found or the end of the `range` is reached. Objects are considered equal if <doc://com.apple.documentation/documentation/ObjectiveC/NSObjectProtocol/isEqual(_:)> returns <doc://com.apple.documentation/documentation/Swift/true>.

This method raises an [`rangeException`](/documentation/Foundation/NSExceptionName/rangeException) exception if the `range` parameter represents a range that doesn’t exist in the array.

## See Also

[`-  containsObject:`](/documentation/Foundation/NSArray/contains(_:))

Returns a Boolean value that indicates whether a given object is present in the array.


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