---
title: "double(forKey:)"
framework: foundation
role: symbol
role_heading: Instance Method
path: "foundation/userdefaults/double(forkey:)"
---

# double(forKey:)

Returns the double value associated with the specified key.

## Declaration

```swift
func double(forKey defaultName: String) -> Double
```

## Parameters

- `defaultName`: The key to retrieve from the defaults database.

## Return Value

Return Value The double value associated with defaultName, or 0.0 if the key isn’t present in the defaults database.

## Discussion

Discussion This method automatically coerces certain types to their equivalent double values. The Boolean value true becomes 1.0 and false becomes 0.0. An integer becomes the equivalent double –– for example, 2 becomes 2.0. A string that contains a numerical value contains the equivalent double — for example, “123.4” becomes 123.4.

## See Also

### Getting the value of a key

- [bool(forKey:)](foundation/userdefaults/bool(forkey:).md)
- [integer(forKey:)](foundation/userdefaults/integer(forkey:).md)
- [float(forKey:)](foundation/userdefaults/float(forkey:).md)
- [url(forKey:)](foundation/userdefaults/url(forkey:).md)
- [string(forKey:)](foundation/userdefaults/string(forkey:).md)
- [stringArray(forKey:)](foundation/userdefaults/stringarray(forkey:).md)
- [data(forKey:)](foundation/userdefaults/data(forkey:).md)
- [object(forKey:)](foundation/userdefaults/object(forkey:).md)
- [array(forKey:)](foundation/userdefaults/array(forkey:).md)
- [dictionary(forKey:)](foundation/userdefaults/dictionary(forkey:).md)
- [dictionaryRepresentation()](foundation/userdefaults/dictionaryrepresentation().md)