日付や時刻まわりのSnippet ref: http://qiita.com/katsuhide@github/items/887ad9466d0faa695e33

file0.swift

//現在時刻
let now = NSDate()

let cal = NSCalendar(identifier: NSCalendarIdentifierGregorian)!
//10日後
let in10days = cal.dateByAddingUnit(.Day, value: 10, toDate: now, options: NSCalendarOptions())

//2日前
let ago2days = cal.dateByAddingUnit(.Day, value: -2, toDate: now, options: NSCalendarOptions())

//1年前
let ago1year = cal.dateByAddingUnit(.Year, value: -1, toDate: now, options: NSCalendarOptions())

//日付の比較
cal.isDate(now, inSameDayAsDate: in10days!)

//年月など単位を指定して比較
cal.isDate(now, equalToDate: in10days!, toUnitGranularity: .Month)

cal.isDate(now, equalToDate: ago2days!, toUnitGranularity: .Month)

cal.isDate(now, equalToDate: ago1year!, toUnitGranularity: .Month)

cal.isDate(now, equalToDate: ago1year!, toUnitGranularity: .Day)

cal.isDate(now, equalToDate: now, toUnitGranularity: .Day)