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# lowercased(with:)

Returns a version of the string with all letters converted to lowercase, taking into account the specified locale.

```
func lowercased(with locale: Locale?) -> String
```

## Parameters

`locale`

The locale. For strings presented to users, pass the current locale ([[`NSLocale`](/documentation/Foundation/NSLocale) [`current`](/documentation/Foundation/NSLocale/current)]). To use the system locale, pass `nil`.

## Return Value

A lowercase string using the `locale`.

## Discussion

Case transformations aren’t guaranteed to be symmetrical or to produce strings of the same lengths as the originals. See [`lowercased`](/documentation/Foundation/NSString/lowercased) for an example.

---

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