Swift: working with String

How to remove diacritics from a String in Swift?
http://stackoverflow.com/a/29522097

let foo = "één"
let bar = foo.stringByFoldingWithOptions(.DiacriticInsensitiveSearch, locale: NSLocale.currentLocale())
println(bar) // een

Format number to string:
let formatted = NSString(format: "04d%02d", 1233, 14)

Get substring:
let startDate = "201409"
let year = startDate.substringWithRange(Range<String.Index>(start: advance(startDate.startIndex, 0), end: advance(startDate.endIndex, -2)))     // 2014
let month = startDate.substringWithRange(Range<String.Index>(start: advance(startDate.startIndex, 4), end: advance(startDate.endIndex, 0))) // 09

Check substring exist
if "hello Swift".rangeOfString("hello") != nil{
    println("exists")
}

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