Swift Extensions... These are extensions to Swift standard types that I find useful.

DictionaryExtensions.swift

//
//  DictionaryExtensions.swift
//
//  Created by Daniel Tartaglia on 6/18/16.
//  Copyright © 2016 Daniel Tartaglia. MIT License.
//


extension Dictionary {

    /// An immutable version of update. Returns a new dictionary containing self's values and the key/value passed in.
    func updatedValue(_ value: Value, forKey key: Key) -> Dictionary<Key, Value> {
        var result = self
        result[key] = value
        return result
    }
}

SequenceTypeExtensions.swift

//
//  SequenceExtensions.swift
//
//  Created by Daniel Tartaglia on 6/10/16.
//  Copyright © 2016 Daniel Tartaglia. MIT License.
//


extension Sequence where Iterator.Element: Hashable {
    /// returns an array of elements filtered to ensure that no elements are duplicated.
    func unique() -> [Iterator.Element] {
        return reduce((Set<Iterator.Element>(), Array<Iterator.Element>())) { current, name in
            guard current.0.contains(name) == false else { return current }
            return (current.0.inserted(name), current.1 + [name])
            }.1
    }
}

extension Sequence where Iterator.Element: Equatable {

    /// Returns true if every element is equal to the first element.
    /// Returns true if the sequence is empty.
    func allEqual() -> Bool {
        return allEqual({ $0 == $1 })
    }

}

extension Sequence {

    /// Returns true if every element satisfies the predicate.
    func all(are pred: (Iterator.Element) -> Bool) -> Bool {
        return !contains(where: { !pred($0) })
    }

    /// Returns true if every element is equal to the first element according to the pred passed in.
    /// Returns true if the sequence is empty.
    func allEqual(_ pred: (Iterator.Element, Iterator.Element) -> Bool) -> Bool {
        var first: Iterator.Element?
        for each in self {
            if let first = first {
                if !pred(first, each) {
                    return false
                }
            }
            else {
                first = each
            }
        }
        return true
    }
}

SetExtensions.swift

//
//  SetExtensions.swift
//
//  Created by Daniel Tartaglia on 6/10/16.
//  Copyright © 2016 Daniel Tartaglia. MIT License.
//

extension Set {

    /// returns a new set with `member` added.
    func inserted(_ member: Element) -> Set {
        var result = self
        result.insert(member)
        return result
    }
}

StringExtensions.swift

//
//  StringExtensions.swift
//  
//  Created by Daniel Tartaglia on 6/10/16.
//  Copyright © 2016 Daniel Tartaglia. MIT License
//

import Foundation

extension String {
	
	/// Converts an NSRange across a String into a swift Range type.
    // from http://stackoverflow.com/questions/25138339/nsrange-to-rangestring-index
	func rangeFromNSRange(nsRange : NSRange) -> Range<String.Index> {
        let from16 = utf16.index(utf16.startIndex, offsetBy: nsRange.location)
        let to16 = utf16.index(from16, offsetBy: nsRange.length)
        if let from = String.Index(from16, within: self),
            let to = String.Index(to16, within: self) {
            return from ..< to
        }
        fatalError()
    }

    func occurences(of text: String) -> Int {
        var result = 0
        var index = startIndex
        while index < endIndex, let range = range(of: text, range: index..<endIndex) {
            result += 1
            index = range.upperBound
        }
        return result
    }
}