"I love Dollar and Cent - Underscore.js for Swift"

2022-05-04 02:41:21

Dollar and Cent View on GitHub Issues Dollar Contents Setup Using cocoapods version 0.36.x or greater Using Swift Package Manager Using git submodule Support for Xcode and Swift Demo Apps Communication Dollar Usage Array at - Dollar.at chunk - Dollar.chunk compact - Dollar.compact contains - Dollar.contains cycle - Dollar.cycle difference - Dollar.difference each - Dollar.each every - Dollar.every factorial Dollar.factorial fetch - Dollar.fetch fill - Dollar.fill find - Dollar.find findIndex - Dollar.findIndex findLastIndex - Dollar.findLastIndex first - Dollar.first(array: AnyObject[]) groupBy Dollar.groupBy second - Dollar.second(array: AnyObject[]) flatMap - Dollar.flatMap flatMap - Dollar.flatMap flatten - Dollar.flatten frequencies - Dollar.frequencies gcd Dollar.gcd indexOf - Dollar.indexOf initial - Dollar.initial intersection - Dollar.intersection it-isIn Dollar.it(i: T, isIn range: Range) last - Dollar.last lastIndexOf - Dollar.lastIndexOf lcm Dollar.lcm rest - Dollar.rest map - Dollar.map min - Dollar.min max - Dollar.max pluck - Dollar.pluck pull - Dollar.pull pullAt - Dollar.pullAt range - Dollar.range reduce - Dollar.reduce sample - Dollar.sample sequence - Dollar.sequence remove - Dollar.remove remove - Dollar.remove shuffle - Dollar.shuffle size - Dollar.size sortedIndex - Dollar.sortedIndex transpose - Dollar.transpose union - Dollar.union merge - Dollar.merge uniq - Dollar.uniq without - Dollar.without xor - Dollar.xor zip - Dollar.zip zipObject - Dollar.zipObject partition - Dollar.partition partitionAll - Dollar.partitionAll partitionBy - Dollar.partitionBy Dictionary keys - Dollar.keys values - Dollar.values merge - Dollar.merge pick - Dollar.pick omit - Dollar.omit Object tap - Dollar.tap Function after - Dollar.after bind - Dollar.bind compose - Dollar.compose curry - Dollar.curry id - Dollar.id memoize - Dollar.memoize noop - Dollar.noop now - Dollar.now once - Dollar.once partial - Dollar.partial times - Dollar.times Chaining any all each filter first second third flatten initial map size slice value Cent Usage Array Extensions [Element] at(indexes: Int...) -> [Element] each(callback: (Element) -> ()) -> [Element] eachWithIndex(callback: (Int, Element) -> ()) -> [Element] cycle(times: Int, callback: (Element) -> U) every(callback: (Element) -> Bool) -> Bool indexOf(value: T) -> Int fetch(index: Int, orElse: T? = .None) -> T! findIndex(callback: (Element) -> Bool) -> Int? findLastIndex(callback: (Element) -> Bool) -> Int? first() -> Element? flatten() -> [Element] get(index: Int) -> Element? initial(numElements: Int? = 1) -> [Element] last() -> Element? rest(numElements: Int? = 1) -> [Element] min() -> T? max() -> T? remove(value: T) -> T? contains(value: T) -> Bool Character Extensions "A".description -> String "A".ord -> Int Date Extensions Date.from(#year: Int, month: Int, day: Int) -> NSDate Date.from(#unix: Double) -> NSDate Date.parse(dateStr: String, format: String = "yyyy-MM-dd") -> NSDate Date.unix(date: NSDate = NSDate()) -> Double Int.hour.fromNow et al. Dictionary Extensions merge(dictionaries: Dictionary...) Int Extensions times(callback: (Int) -> ()) times (function: () -> ()) char -> Character isEven isOdd digits() -> [Int] lcm() -> Int gcd() -> Int random() -> Int factorial() -> Int isIn(interval) -> Bool next() -> Int prev() -> Int upTo(limit: Int, callback: () -> ()) downTo(limit: Int, callback: () -> ()) String Extensions .length .camelCase .kebabCase .snakeCase .startCase =~ str: String -> Bool * n: Int -> String [i: Int] -> Character? [str: String] -> String? [r: Range] -> String indexOf(char: Character) -> Int? indexOf(str: String) -> Int? indexOf(pattern: String) -> Int? split(delimiter: Character) -> [String] lstrip() -> String rstrip() -> String strip() -> String Regex init matches(testStr: String) -> [AnyObject] test(testStr: String) -> Bool escapeStr(str: String) -> String Range Extensions equals - == eachWithIndex(callback: (T) -> ()) each(callback: () -> ()) Contributing Dollar Dollar is a Swift library that provides useful functional programming helper methods without extending any built in objects. It is similar to Lo-Dash or Underscore.js in Javascript. Cent is a library that extends certain Swift object types using the extension feature and gives its two cents to Swift language. It is now moved into a separate repo to support Swift Package Manager NOTE: Starting Swift 4 $ is no longer a valid identifier. So you get the following error: '$' is not an identifier; use backticks to escape it You will need to espace $ identifier using backticks. Contents Setup Demo App API Documentation Usage Array Dictionary Object Function Chaining Contributing Setup Using cocoapods version 0.36.x or greater Add pod 'Dollar' to your Podfile and run pod install. Add use_frameworks! to the end of the Podfile. Also checkout this sample app. Using Swift Package Manager Add the following dependency .Package(url: "https://github.com/ankurp/Dollar", majorVersion: 7, minor: 1) to your Package.swift file and then run swift build. Requires swift version 2.2 or greater that you can install from https://swift.org Using git submodule If you are using git then add Dollar as a submodule using git submodule add https://github.com/ankurp/Dollar.git. If not using git download the project using git clone https://github.com/ankurp/Dollar.git in your project folder. Open the Dollar folder. Drag Dollar.xcodeproj, inside the Dollar folder, into the file navigator of your Xcode project. In Xcode, navigate to the target configuration window by clicking on the blue project icon, and selecting the application target under the “Targets” heading in the sidebar. In the tab bar at the top of that window, open the “Build Phases” panel. Expand the “Link Binary with Libraries” group, and add Dollar.framework. In your project file import Dollar and you can call all of the helper functions. Still stuck. Then checkout this screencast on how to import Support for Xcode and Swift For Xcode 9 (Swift 4) user version 7.1.0 For Xcode 8 (Swift 3) user version 6.0.0 For Xcode 7 (Swift 2) use version 4.1.0 or 5.2.0 For Xcode 6.3 (Swift 1.2) use version 3.0.3 For Xcode 6.1 and 6.2 (Swift 1.1) use version 2.2.0 Demo Apps Using Cocoa Pods Using Swift Package Manager Using git submodule Communication If you need help, use gitter.im or post a question on Stack Overflow with tag dollar.swift. If you’d like to ask a general question, use Stack Overflow. If you found a bug, open an issue. If you have a feature request, open an issue. If you want to contribute, submit a pull request. Dollar Usage Array at - Dollar.at Creates an array of elements from the specified indexes, or keys, of the collection. Indexes may be specified as individual arguments or as arrays of indexes.Dollar.at(["ant", "bat", "cat", "dog", "egg"], indexes: 0, 2, 4) => ["ant", "cat", "egg"] chunk - Dollar.chunk Creates an array of elements split into groups the length of size. If array can’t be split evenly, the final chunk will be the remaining elements.Dollar.chunk([1, 2, 3, 4], size: 2)=> [[1, 2], [3, 4]]Dollar.chunk([1, 2, 3, 4], size: 3)=> [[1, 2, 3], [4]] compact - Dollar.compact Creates an array with all nil values removed.Dollar.compact([3, nil, 4, 5]) => [3, 4, 5]Dollar.compact([nil, nil]) as NSObject[] => [] contains - Dollar.contains Checks if a given value is present in the array.Dollar.contains([1, 2, 3, 1, 2, 3], value: 2) => trueDollar.contains([1, 2, 3, 1, 2, 3], value: 10) => false cycle - Dollar.cycle Cycles through the array definetly or indefinetly passing each element into the callback function. The second parameter is to specify how many times to cycle through the array. If left out it will cycle indefinetly.Dollar.cycle([1, 2, 3], 2) { print($0)}// Prints the following123123 difference - Dollar.difference Creates an array excluding all values of the provided arraysDollar.difference([1, 2, 3, 4, 5], [5, 2, 10]) => [1, 3, 4] each - Dollar.each Passes each element in the array to the callbackDollar.each(["A", "B"]) { print("Value \($0)")}=> ["A", "B"]Dollar.each(["A", "B"]) { (index, elem) in print("\(index) - \(elem)")}=> ["0 - A", "1 - B"] every - Dollar.every Checks if the given callback returns true value for all items in the array.Dollar.every([1, 2, 3, 4], callback: { $0 < 20 }) => trueDollar.every([1, 2, 3, 4]) { $0 == 1 } => false factorial Dollar.factorial Returns factorial of integerDollar.factorial(3)=> 6Dollar.factorial(0)=> 1 fetch - Dollar.fetch Get element from an array at the given index which can be negative to find elements from the end of the array. A default value can be returned if indexing out of bounds.let arr = [1, 2, 3, 4, 5, 6, 7, 8]Dollar.fetch(arr, 100)=> nilDollar.fetch(arr, 100, orElse: 42)=> 42Dollar.fetch(arr, -1)=> 8 fill - Dollar.fill Fills elements of array with value from start up to, but not including, end. This method mutates array.var arr = Array(count: 5, repeatedValue: 1)Dollar.fill(&arr, withElem: 42)=> [42, 42, 42, 42, 42]var arr = Array(count: 5, repeatedValue: 1)Dollar.fill(&arr, withElem: 42, startIndex: 1, endIndex: 3)=> [1, 42, 42, 42, 1] find - Dollar.find Iterates over elements of an array and returning the first element that the callback returns true for.Dollar.find([1, 2, 3, 4], callback: { $0 == 2 }) => 2Dollar.find([1, 2, 3, 4]) { $0 == 10 } => nil findIndex - Dollar.findIndex This method is like find except that it returns the index of the first element that passes the callback check.let arr = [["age": 36], ["age": 40], ["age": 1]]let result = Dollar.findIndex(arr) { $0["age"] < 20 }result => 2 findLastIndex - Dollar.findLastIndex This method is like findIndex except that it iterates over elements of the array from right to left.let arr = [["age": 36], ["age": 40], ["age": 1]]let result = Dollar.findLastIndex(arr) { $0["age"] > 30 }result=> 1 first - Dollar.first(array: AnyObject[]) Gets the first element in the array.Dollar.first([1, 2, 3, 4])=> 1Dollar.first([]) => nil groupBy Dollar.groupBy This method returns a dictionary of values grouped by the value returned by a callback.Dollar.groupBy([1, 2, 3, 4, 5], callback: {$0 % 2})=> [0: [2, 4], 1: [1, 3]]Dollar.groupBy(["strings", "with", "different", lengths"], callback: {$0.characters.count})=> [7: ["strings", "lengths"], 9: ["different"], 4: ["With"]] second - Dollar.second(array: AnyObject[]) Gets the second element in the array.Dollar.second([1, 2, 3, 4])=> 2Dollar.second([1]) => nilDollar.second([])=> nil flatMap - Dollar.flatMap Maps a function that converts elements to a list and then concatenates them.let values = [2, 3, 4, 5, 6, 7]Dollar.flatMap(values) { [$0, $0] }=> [2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7] flatMap - Dollar.flatMap Maps a function that converts a type to an Optional over an Optional, and then returns a single-level Optional.let url = NSURL(string: "https://apple.com/swift")Dollar.flatMap(url) { $0.lastPathComponent }=> Optional("swift") Note: This is the same behavior as Optional chaining. The code above translates toNSURL(string: "https://apple.com/swift/")?.lastPathComponent=> Optional("swift") flatten - Dollar.flatten Flattens a nested array of any depth.Dollar.flatten([[3], 4, 5]) as Int[] => [3, 4, 5]Dollar.flatten([[3], "Hello", 5]) as NSObject[] => [3, "Hello", 5]Dollar.flatten([[[3], 4], 5]) as Int[] => [3, 4, 5] frequencies - Dollar.frequencies This method returns a dictionary of values in an array mapping to the total number of occurrences in the array. If passed a function it returns a frequency table of the results of the given function on the arrays elements.Dollar.frequencies(["a", "a", "b", "c", "a", "b"]) => ["a": 3, "b": 2, "c": 1]Dollar.frequencies([1, 2, 3, 4, 5]) { $0 % 2 == 0 }=> [false: 3, true: 2] gcd Dollar.gcd GCD function return greatest common denominator with number passedDollar.gcd(3, 10)=> 1Dollar.gcd(3, 9)=> 3 indexOf - Dollar.indexOf Gets the index at which the first occurrence of value is found.Dollar.indexOf([1, 2, 3, 1, 2, 3], value: 2) => 1Dollar.indexOf(["A", "B", "C"], value: "B") => 1Dollar.indexOf([3, 4, 5], value: 5) => 2Dollar.indexOf([3, 4, 5], value: 3) => 0Dollar.indexOf([3, 4, 5], value: 2) => nil initial - Dollar.initial Gets all but the last element or last n elements of an array.Dollar.initial([3, 4, 5]) => [3, 4]Dollar.initial([3, 4, 5], numElements: 2) => [3] intersection - Dollar.intersection Creates an array of unique values present in all provided arrays.Dollar.intersection([1, 2, 3], [5, 2, 1, 4], [2, 1]) => [1, 2] it-isIn Dollar.it(i: T, isIn range: Range) Returns true if i is in interval or rangeDollar.it("c", isIn: "a"..."z")=> trueDollar.it("z", isIn: "a".. falseDollar.it(1, isIn: -1.0...10.0)=> true last - Dollar.last Gets the last element from the array.Dollar.last([3, 4, 5]) => 5 lastIndexOf - Dollar.lastIndexOf Gets the index at which the last occurrence of value is found.Dollar.lastIndexOf([1, 2, 3, 1, 2, 3], value: 2) => 4 lcm Dollar.lcm LCM method return least common multiple with number passedDollar.lcm(3, 10)=> 30Dollar.lcm(3, 9)=> 9 rest - Dollar.rest The opposite of initial this method gets all but the first element or first n elements of an array.Dollar.rest([3, 4, 5]) => [4, 5]Dollar.rest([3, 4, 5], numElements: 2) => [5] map - Dollar.map Maps each element to new value based on the map function passedDollar.map([1, 2, 3, 4]) { $0 * 2}=> [2, 4, 6, 8] min - Dollar.min Retrieves the minimum value in an array.Dollar.min([2, 1, 2, 3, 4]) => 1 max - Dollar.max Retrieves the maximum value in an array.Dollar.max([1, 2, 3, 4, 2, 1]) => 4 pluck - Dollar.pluck Retrieves the value of a specified property from all elements in the array.let arr = [["age": 20], ["age": 30], ["age": 40]]Dollar.pluck(arr, value: "age") => [20, 30, 40] pull - Dollar.pull Removes all provided values from the given array.Dollar.pull([3, 4, 5, 3, 5], values: 3, 5) => [4]Dollar.pull([3, 4, 5, 3, 5], values: 4) => [3, 5, 3, 5]Dollar.pull([3, 4, 5, 3, 5], values: 3, 4, 5) => [] pullAt - Dollar.pullAt Removes all provided values from the given array at the given indiceslet arr = [10, 20, 30, 40, 50]Dollar.pullAt(arr, indices: 1, 2, 3) range - Dollar.range Creates an array of numbers (positive and/or negative) progressing from start up to but not including end.Dollar.range(4) => [0, 1, 2, 3]Dollar.range(from: 1, to: 5) => [1, 2, 3, 4]Dollar.range(from: 0, to: 20, incrementBy: 5) => [0, 5, 10, 15]Dollar.range(from: 1, through: 5)=> [1, 2, 3, 4, 5]Dollar.range(from: 0, through: 20, incrementBy: 5)=> [0, 5, 10, 15, 20] reduce - Dollar.reduce Reduce function that will resolve to one value after performing combine function on all elementsDollar.reduce([1, 2, 3], initial: 0) { (total, element) in total + element}=> 6 sample - Dollar.sample Returns a sample item from the arraylet arr : Int[] = [2, 1, 2, 3, 4]Dollar.contains(arr, value: Dollar.sample(arr))=> true sequence - Dollar.sequence Creates an array of an arbitrary sequence. Especially useful with builtin ranges.Dollar.sequence(0..4) => [0, 1, 2, 3]Dollar.sequence(-2.0..2.0) => [-2.0, -1.0, 0.0, 1.0]Dollar.sequence((0..20).by(5)) => [0, 5, 10, 15]Dollar.sequence("abc") => ["a", "b", "c"] remove - Dollar.remove Removes an element from array.Dollar.remove(["A", "B", "C", "D"], value: "B")=> ["A", "C", "D"] remove - Dollar.remove Removes all elements from an array that the callback returns true.let result = Dollar.remove([1, 2, 3, 4, 5, 6]) { $0 == 2 || $0 == 3 }result=> [1, 4, 5, 6] shuffle - Dollar.shuffle Shuffles and returns the new shuffled arraylet result = Dollar.shuffle([1, 2, 3, 4, 5, 6])result=> [4, 1, 3, 5, 6, 2] size - Dollar.size Returns size of the arrayDollar.size(["a", "b", "c")=> 3 sortedIndex - Dollar.sortedIndex Gives the smallest index at which a value should be inserted into a given the array is sorted.Dollar.sortedIndex([3, 4, 6, 10], value: 5)=> 2Dollar.sortedIndex([10, 20, 30, 50], value: 40)=> 3 transpose - Dollar.transpose Creates a tranposed matrix.Dollar.transpose([[1, 2, 3], [4, 5, 6]])=> [[1, 4], [2, 5], [3, 6]] union - Dollar.union Creates an array of unique values, in order, of the provided arrays.Dollar.union([1, 2, 3], [5, 2, 1, 4], [2, 1]) => [1, 2, 3, 5, 4] merge - Dollar.merge Creates an array of all values, including duplicates, of the arrays in the order they are provided.let arr = [1, 5]let arr2 = [2, 4]let arr3 = [5, 6]let result = Dollar.merge(arr, arr2, arr3)result=> [1, 5, 2, 4, 5, 6] uniq - Dollar.uniq Creates a duplicate-value-free version of an array.Dollar.uniq([1, 2, 1, 3, 1])=> [1, 2, 3]Dollar.uniq([1, 2.5, 3, 1.5, 2, 3.5]) { floor($0)}=> [1, 2.5, 3] without - Dollar.without Creates an array excluding all provided values.Dollar.without([3, 4, 5, 3, 5], values: 3, 5)=> [4]Dollar.without([3, 4, 5, 3, 5], values: 4)=> [3, 5, 3, 5]Dollar.without([3, 4, 5, 3, 5], values: 3, 4, 5)=> [] xor - Dollar.xor Creates an array that is the symmetric difference of the provided arrays.Dollar.xor([1, 2, 3], [5, 2, 1, 4])=> [3, 4, 5] zip - Dollar.zip Creates an array of grouped elements, the first of which contains the first elements of the given arrays.Dollar.zip(["fred", "barney"], [30, 40], [true, false]) as [NSObject] => [["fred", 30, true], ["barney", 40, false]] zipObject - Dollar.zipObject Creates an object composed from arrays of keys and values.Dollar.zipObject(["fred", "barney"], values: [30, 40])=> ["fred": 30, "barney": 40] partition - Dollar.partition Produces an array of arrays, each containing n elements, each offset by step. Stops after a partition is less than n length.let arr = [1, 2, 3, 4, 5]Dollar.partition(arr, n: 2)=> [[1, 2], [3, 4]]Dollar.partition(arr, n: 4, step: 1)=> [[1, 2, 3, 4], [2, 3, 4, 5]]Dollar.partition(arr, n: 4, step: 1, pad: nil)=> [[1, 2, 3, 4], [2, 3, 4, 5], [3, 4, 5]]Dollar.partition(arr, n: 4, step: 1, pad: [6, 7, 8])=> [[1, 2, 3, 4], [2, 3, 4, 5], [3, 4, 5, 6]] partitionAll - Dollar.partitionAll Produces an array of arrays, each containing n elements, each offset by step. Continues after a partition is less than n length.Dollar.partitionAll([1, 2, 3, 4, 5], n:4, step: 1)=> [[1, 2, 3, 4], [2, 3, 4, 5], [3, 4, 5], [4, 5], [5]] partitionBy - Dollar.partitionBy Applies a function to each element in array, splitting it each time the function returns a new value.Dollar.partitionBy([1, 2, 3, 4, 5]) { $0 % 2 == 0 }=> [[1], [2, 4], [3, 5], [6]]Dollar.partitionBy([1, 7, 3, 6, 10, 12]) { $0 % 3 }=> [[1, 7], [3, 6], [10], [12]] Dictionary keys - Dollar.keys Creates an array of keys given a dictionary.Dollar.keys(["Dog": 1, "Cat": 2])=> ["Dog", "Cat"] values - Dollar.values Creates an array of values given a dictionaryDollar.values(["Dog": 1, "Cat": 2])=> [1, 2] merge - Dollar.merge Merges all of the dictionaries together and the latter dictionary overrides the value at a given keylet dict: Dictionary = ["Dog": 1, "Cat": 2]let dict2: Dictionary = ["Cow": 3]let dict3: Dictionary = ["Sheep": 4]Dollar.merge(dict, dict2, dict3)=> ["Dog": 1, "Cat": 2, "Cow": 3, "Sheep": 4] pick - Dollar.pick Creates a shallow clone of a dictionary composed of the specified keys.Dollar.pick(["Dog": 1, "Cat": 2, "Cow": 3], keys: "Dog", "Cow")=> ["Dog": 1, "Cow": 3] omit - Dollar.omit Creates a shallow clone of a dictionary excluding the specified keys.Dollar.omit(["Dog": 1, "Cat": 2, "Cow": 3, "Sheep": 4], keys: "Cat", "Dog")=> ["Cow": 3, "Sheep": 4] Object tap - Dollar.tap Invokes interceptor with the object and then returns object.var beatle = Car(name: "Fusca")Dollar.tap(beatle, {$0.name = "Beatle"}).color = "Blue" Function after - Dollar.after Creates a function that executes passed function only after being called n times.var saves = ["profile", "settings"];let asyncSave = { (function: () -> ()?) in function() // Saving right away for testing // but in real world would be async}var isDone = falsevar completeCallback = Dollar.after(saves.count) { isDone = true}for elem in saves { asyncSave(completeCallback)}isDone => true bind - Dollar.bind Creates a function that, when called, invokes func with the binding of arguments provided.var helloWorldFunc = Dollar.bind({(T...) in T[0] + " " + T[1] + " from " + T[2] }, "Hello", "World", "Swift")helloWorldFunc() => "Hello World from Swift"helloWorldFunc = Dollar.bind({ $0 + " World" }, "Hello")helloWorldFunc()=> "Hello World"helloWorldFunc = Dollar.bind({ $0 + $1 + " World" }, "Hello ", "Great")helloWorldFunc()=> "Hello Great World" compose - Dollar.compose Compose two or more functions where the return value of the first function is passed into the next function. Useful when chaining functions and returns a function that can be called with variadic argument values or an array of values as inputlet double = { (params: Int...) -> [Int] in return Dollar.map(params) { $0 * 2 }}let subtractTen = { (params: Int...) -> [Int] in return Dollar.map(params) { $0 - 10 }}let doubleSubtractTen = Dollar.compose(double, subtractTen)doubleSubtractTen(5, 6, 7)=> [0, 2, 4]let f = Dollar.compose({ (arr: [Int]) -> [Int] in Dollar.map(arr) { $0 + 1 }}, { (arr: [Int]) -> [Int] in Dollar.map(arr) { $0 * 2 }})f([1, 2])=> [4, 6] curry - Dollar.curry Returns a function which when invoked either executes the function returning its result, if all function arguments have been provided, or returns another function that accepts one more argument of the remaining function arguments until all arguments are supplied. This is useful for making partial function as seen in these examples.func adder(x: Int, y: Int, z: Int) -> Int {return x + y + z}let curriedAdder = Dollar.curry(adder)let addTenAnd = curriedAdder(10)let addThirtyAnd = addTenAnd(20)addThirtyAnd(1)=> 31addThirtyAnd(50)=> 80addTenAnd(10)(10)=> 30 id - Dollar.id The identify function which simply returns the argument its given.Dollar.id("Hello World from Swift")=> "Hello World from Swift" memoize - Dollar.memoize Returns a memoized function to improve performance by caching recursive function values.var times = 0 // to test memoizationlet fibMemo = Dollar.memoize { (fib: (Int -> Int), val: Int) -> Int in times += 1 return val == 1 || val == 0 ? 1 : fib(val - 1) + fib(val - 2)}let x = fibMemo(5)times=> 6times = 0let y = fibMemo(5)times=> 0times = 0let z = fibMemo(6)times=> 1 noop - Dollar.noop A no-operation function.Dollar.noop() => nil now - Dollar.now Gets the number of seconds that have elapsed since the Unix epoch (1 January 1970 00:00:00 UTC).Dollar.now() => 1431911564.292577 once - Dollar.once Get a wrapper function that executes the passed function only once. Useful for getting shared config or creating singleton objects.func createConfig() -> [String: String] { var i = 1 return [ "App ID": "\(i++)", "URL": "https://someurl" ]}let getConfig = Dollar.once(createConfig)getConfig()=> ["App ID": "1", "URL": "https://someurl"]getConfig()=> ["App ID": "1", "URL": "https://someurl"] partial - Dollar.partial Creates a function that, when called, invokes func with any additional partial arguments prepended to those provided to the new function.let partialFunc = Dollar.partial({(T...) in T[0] + " " + T[1] + " from " + T[2] }, "Hello")partialFunc("World", "Swift") => "Hello World from Swift" times - Dollar.times Call a function n times and also passes the index. If a value is returned in the function then the times method will return an array of those values.let fun = Dollar.bind({ (names: String...) -> String in let people = Dollar.join(names, separator: " from ") return "Hello \(people)" }, "Ankur", "Swift")Dollar.times(2, function: fun) as String[] => ["Hello Ankur from Swift", "Hello Ankur from Swift"] Chaining Dollar.chain(...) any Returns true if callback function returns true for at least one element in the arrayvar chain = Dollar.chain([1, 2, 3])chain.any({ ($0 as Int) < 2 })=> true all Returns true if callback function returns true for all elements in the arrayvar chain = Dollar.chain([1, 2, 3])chain.all({ ($0 as Int) < 10 })=> true each Passes each element value to the callback functionvar chain = Dollar.chain(["Hello", "World"])var strBuilder = ""chain.each({ strBuilder += ($0 as String) }).valuestrBuilder=> "HelloWorld" filter Filters the arrary to elements for which the callback function returns truevar chain = Dollar.chain([1, 2, 3, 4])chain.filter({ ($0 as Int) < 3 }).value=> [1, 2] first Returns the first element in the array and terminates the chainvar chain = Dollar.chain([1, 2, 3, 4])chain.first()=> 1 second Returns the second element in the array and terminates the chainvar chain = Dollar.chain([1, 2, 3, 4])chain.second()=> 2 third Returns the third element in the array and terminates the chainvar chain = Dollar.chain([1, 2, 3, 4])chain.third()=> 3 flatten Flattens a nested array of any depth.var chain = Dollar.chain([[1, [2]], [3], 4])chain.flatten().value=> [1, 2, 3, 4] initial Gets all but the last element or last n elements of an array.var chain = Dollar.chain([1, 2, 3, 4])chain.initial(2).value=> [1, 2] map Maps each element to the new value returned in the callback functionvar chain = Dollar.chain([1, 2, 3, 4])chain.map({ ($0 as Int) * 2 }).value=> [2, 4, 6, 8] size Returns size of the array and terminates the chainvar chain = Dollar.chain([1, 2, 3, 4])chain.map({ ($0 as Int) * 2 }).size()=> 4 slice Slices the array based on the start and end position. If an end position is not specified it will slice till the end of the array.var chain = Dollar.chain([1, 2, 3, 4, 5, 6, 7])chain.slice(2, end: 4).value=> [3, 4] value Returns the value after evaluating all callbacksvar chain = Dollar.chain([1, 2, 3, 4, 5, 6, 7])chain.value=> [1, 2, 3, 4, 5, 6, 7] Chaining more than one methodDollar.chain([[1, 2], 3, [[4], 5]]) .initial() .flatten() .first()=> 1Dollar.chain([1, 2, 3, 4, 5]) .filter { $0 % 1 == 0 } .map { $0 * 2 } .all {$0 < 10}=> falseDollar.chain([1, 2, 3, 4, 5]) .map({ $0 * 2 }) .flatten() .initial(2).value=> [2, 4, 6] Cent Usage Array Extensions [Element] Overloaded operator to append element to an array or append elements from another array into the first array. Return array with the element appended in the end.var array = [1, 2, 3]array [1, 2, 3, 4]array [1, 2, 3, 4, 5, 6] at(indexes: Int...) -> [Element] Creates an array of elements from the specified indexes, or keys, of the collection.let array = ["foo", "spam", "bar", "eggs"]let some = array.at(1, 3)=> ["spam", "eggs"] each(callback: (Element) -> ()) -> [Element] For each item in the array invoke the callback by passing the elemlet array = ["foo", "spam", "bar", "eggs"]array.each { print($0)}=> ["foo", "spam", "bar", "eggs"] eachWithIndex(callback: (Int, Element) -> ()) -> [Element] For each item in the array invoke the callback by passing the elem along with the indexlet array = ["foo", "spam", "bar", "eggs"]array.each { (index, elem) print("\(index) - \(elem)")}=> ["foo", "spam", "bar", "eggs"] cycle(times: Int, callback: (Element) -> U) Cycles through the array definetly or indefinetly passing each element into the callback function. The second parameter is to specify how many times to cycle through the array. If left out it will cycle indefinetly.[1, 2, 3].cycle(2) { print($0)}// Prints the following123123[1, 2, 3].cycle { print($0)}// Cycles in an infinite loop every(callback: (Element) -> Bool) -> Bool Checks if the given callback returns true value for all items in the array.["angry", "hungry"].every { (a: String) -> (Bool) in a.hasSuffix("gry") }=> true indexOf(value: T) -> Int Gets the index at which the first occurrence of value is found.let array = ["foo", "spam", "bar", "eggs"]array.indexOf("spam")=> 1array.indexOf("None")=> nil fetch(index: Int, orElse: T? = .None) -> T! Get element from an array at the given index which can be negative to find elements from the end of the array. A default value can be returned if indexing out of bounds.let arr = [1, 2, 3, 4, 5, 6, 7, 8]arr.fetch(100)=> nilarr.fetch(100, orElse: 42)=> 42arr.fetch(-1)=> 8 findIndex(callback: (Element) -> Bool) -> Int? This method is like find except that it returns the index of the first element that passes the callback check.let ind: int? = ["foo", "bar", "spam", "eggs"].findIndex { $0.length == 4}ind! == 2 => true findLastIndex(callback: (Element) -> Bool) -> Int? This method is like findIndex except that it iterates over elements of the array from right to left.let ind: int? = ["foo", "bar", "spam", "eggs"].findLastIndex { $0.length == 4 }ind! == 3 => true first() -> Element? Gets the first element in the array.let first = ["foo", "bar"].first()=> "foo" flatten() -> [Element] Flattens a nested array of any depth.let unFlattened = ["foo", ["bar"], [["spam"]], [[["eggs"]]] ]let flattened = unFlattened.flatten() => ["foo", "bar", "spam", "eggs"] get(index: Int) -> Element? Get element at indexlet element = ["foo", "bar"].get(0)element!=> "foo"let nothing = ["foo", "bar"].get(1000)=> nil initial(numElements: Int? = 1) -> [Element] Gets all but the last element or last n elements of an array.let initial = ["foo", "bar", "spam"].initial(2) => ["foo"] last() -> Element? Gets the last element from the array.let last = ["foo", "bar"].last() => "bar" rest(numElements: Int? = 1) -> [Element] The opposite of initial this method gets all but the first element or first n elements of an array.let rest = ["foo", "bar", "spam"].rest(2)=> ["spam"] min() -> T? Retrieves the minimum value in an array.let min = [ 0, 1, 2 ].min()=> 0 max() -> T? Retrieves the maximum value in an array.let max = [ 0, 1, 2].max()=> 2 remove(value: T) -> T? Remove element from arrayvar arr = ["A", "B", "C", "D", "E"]arr.remove("B")=> ["A", "C", "D", "E"] contains(value: T) -> Bool Checks if a given value is present in the array.var arr = ["A", "B", "C", "D", "E"]arr.contains("C")=> truearr.contains("Z")=> false Character Extensions "A".description -> String Get string description of Characterlet ch: Character = "A"let str = ch.description=> "A" "A".ord -> Int Get int representation of characterCharacter("A").ord=> 65 Date Extensions Date.from(#year: Int, month: Int, day: Int) -> NSDate Returns a new Date given the year month and daylet date = Date.from(2014, 1, 1) => "Jan 1, 2014, 12:00 AM" Date.from(#unix: Double) -> NSDate Returns a new Date given the unix timestamp (timeIntervalSince1970)let date = Date.from(unix: 1_388_552_400.0)=> "Jan 1, 2014, 12:00 AM" Date.parse(dateStr: String, format: String = "yyyy-MM-dd") -> NSDate Parses the date based on the format and return a new Datelet parsedDate = Date.parse("2014-01-01", format: "yyyy-MM-dd")=> "Jan 1, 2014, 12:00 AM" Date.unix(date: NSDate = NSDate()) -> Double Returns the unix timestamp of the date passed in or the current unix timestamplet currentUnix = Date.unix()=> 1,388,552,400.0var otherNSDate = Date()let otherUnix = Date.unix(otherDate)=> 1,388,552,400.0 Int.hour.fromNow et al. Use the following syntax to calculate dates and times based on the user’s current calendar. 1.day.ago=> "Apr 10, 2015, 11:51 AM"4.hours.fromNow=> "Apr 11, 2015, 3:51 PM" Dictionary Extensions merge(dictionaries: Dictionary...) Merges the dictionary with dictionaries passed. The latter dictionaries will override values of the keys that are already setvar dic = ["foo": "bar"] let anotherDic = ["foo": "baz", "spam": "eggs"]dic.merge(anotherDic)=> ["foo": "baz", "spam": "eggs"] Int Extensions times(callback: (Int) -> ()) Invoke a callback n times with callback that takes index5.times { print("Na") } => "NaNaNaNaNa" times (function: () -> ()) Invoke a callback n times5.times { (a: Int) -> () in print("\(a) ") } => 0 1 2 3 4 char -> Character Get ASCII character from integer65.char=> "A" isEven Check if int is even2.isEven=> true1.isEven=> false isOdd Check if int is odd3.isOdd=> true2.isOdd=> false digits() -> [Int] Splits the int into array of digits4208.digits()=> [4, 2, 0, 8] lcm() -> Int LCM method return least common multiple with number passed3.lcm(10)=> 303.lcm(9)=> 9 gcd() -> Int GCD method return greatest common denominator with number passed3.gcd(10)=> 13.gcd(9)=> 3 random() -> Int Returns random number from 0 upto but not including value of integer3.random()=> 23.random()=> 1 factorial() -> Int Returns factorial of integer3.factorial()=> 60.factorial()=> 1 isIn(interval) -> Bool Returns true if i is in interval or range5.isIn(1...10)=> true10.isIn(1.. false next() -> Int Get the next int10.next()=> 11 prev() -> Int Get the previous int10.prev()=> 9 upTo(limit: Int, callback: () -> ()) Invoke the callback from int up to and including limit3.upTo(5) { print("Hi")}Prints "HiHiHi" downTo(limit: Int, callback: () -> ()) Invoke the callback from int down to and including limit3.downTo(0) { print("Hi")}Prints "HiHiHiHi" String Extensions .length Get the length of the string"Hello".length=> 5 .camelCase Get the camel case representation of the string"__Dollar and cent-- dollarANDCent".camelCase=> "dollarAndCentDollarAndCent" .kebabCase Get the kebab case representation of the string"__Dollar and cent-- dollarANDCent".kebabCase=> "dollar-and-cent-dollar-and-cent" .snakeCase Get the snake case representation of the string"__Dollar and cent-- dollarANDCent".snakeCase=> "dollar_and_cent_dollar_and_cent" .startCase Get the start case representation of the string"__Dollar and cent-- dollarANDCent".startCase=> "Dollar And Cent Dollar And Cent" =~ str: String -> Bool Does a regex match of whether regex string on the right is matches the string on the left"Dollar" =~ "oll"=> true * n: Int -> String Get string concatenated n times"Hi Swift! " * 3=> "Hi Swift! Hi Swift! Hi Swift! " [i: Int] -> Character? Get character at a subscript"Hello World"[6] == "W"=> true"Hi"[5]=> nil [str: String] -> String? Returns the substring based on the first regex match passed in the subscriptlet proj = "Dollar and Cent"proj["^.+[^and Cent]"]=> {Some: "Dollar"} [r: Range] -> String Get substring using subscript notation and by passing a range"Hello World"[0.. true indexOf(char: Character) -> Int? Get the start index of character"hello world".indexOf(Character("o"))!=> 4 indexOf(str: String) -> Int? Get the start index of string"hello world".indexOf("llo")!=> 2"hello world".indexOf("illo")=> nil indexOf(pattern: String) -> Int? Get the start index of regex pattern inside the string"hello world".indexOf(".llo")!=> 1 split(delimiter: Character) -> [String] Get an array from string split using the delimiter character"Hello World".split(" ") => ["Hello", "World"] lstrip() -> String Get string without leading spaceslet leadingSpace = " Hello"leadingSpace.lstrip()=> "Hello" rstrip() -> String Get string without trailing spaceslet trailingSpace = "Hello "trailingSpace.rstrip()=> "Hello" strip() -> String Get string without leading or trailing spaceslet spaces = " Hello "spaces.strip()=> "Hello" Regex init Init with regex pattern as stringRegex.init("^Hello.World$") // Regex that matches "Hello World" matches(testStr: String) -> [AnyObject] Return matches based on String passed.let re = Regex.init("^Hello.World$")re.matches("Hello World") test(testStr: String) -> Boollet re = Regex.init("^Hello.World$")re.test("Hello World")=> truere.test("Str")=> false escapeStr(str: String) -> String Escape string with regex charactersRegex.escape("Hello.World")=> "Hello\.World" Range Extensions equals - == Check the equality of two ranges(1...5) == (1...5) => true(1.. false eachWithIndex(callback: (T) -> ()) For each index in the range invoke the callback by passing the item in range(1...5).eachWithIndex { (a: Int) -> () in print("\(a)") } => 12345 each(callback: () -> ()) For each index in the range invoke the callback(1...5).each { print("Na") } => "NaNaNaNaNa" Contributing If you are interested in contributing checkout CONTRIBUTING.md