In the repository Sorting you'll find multiple sorting algorithms, such as QuickSort, InsertionSort, BubbleSort, etc. Hopefully in the future they will be implemented in as many languages as possible, e.g. in Swift, Java, C#, Python, C++, F#, ...
If you want to know more about a specific algorithm or want to have a cleaner, more general implementation, please also visit the wiki.
Because Swift is a pretty rapidly evolving programming language, some implementations might not be correct anymore. They were written with Swift 2 and will constantly be updated, but depending on the changes, it could take some time.