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 carthage and upcoming 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.

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. Requires cocoapod version 0.36.x or greater.

Using Swift Package Manager

Add the following dependency .Package(url: "https://github.com/ankurp/Dollar", majorVersion: 6, minor: 0) 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) use version 7.0.0
For Xcode 8 (Swift 3) use version 6.2.1
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

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 - `$.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.

$.at(["ant", "bat", "cat", "dog", "egg"], indexes: 0, 2, 4) 
=> ["ant", "cat", "egg"]

chunk - `$.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.

$.chunk([1, 2, 3, 4], size: 2)
=> [[1, 2], [3, 4]]

$.chunk([1, 2, 3, 4], size: 3)
=> [[1, 2, 3], [4]]

compact - `$.compact`

Creates an array with all nil values removed.

$.compact([3, nil, 4, 5]) 
=> [3, 4, 5]

$.compact([nil, nil]) as NSObject[] 
=> []

contains - `$.contains`

Checks if a given value is present in the array.

$.contains([1, 2, 3, 1, 2, 3], value: 2) 
=> true

$.contains([1, 2, 3, 1, 2, 3], value: 10) 
=> false

cycle - `$.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.

$.cycle([1, 2, 3], 2) {
  print($0)
}
// Prints the following
123123

delay - `$.delay`

Delays the execution of a function by the specified DispatchTimeInterval

$.delay(by: .seconds(2)) {
  print("Hello delayed by 2 seconds")
}
=> "Hello delayed by 2 seconds"

debounce - `$.debounce`

Debounce a function such that the function is only invoked once no matter how many times it is called within the delayBy interval

let printQueue = $.debounce(delayBy: .seconds(1)) {
    print("Hello Queue!")
}
for _ in 0...9 {
    printQueue()
}
$.delay(by: .seconds(2), printQueue)
=> "Hello Queue!"
=> "Hello Queue!"

difference - `$.difference`

Creates an array excluding all values of the provided arrays

$.difference([1, 2, 3, 4, 5], [5, 2, 10]) 
=> [1, 3, 4]

each - `$.each`

Passes each element in the array to the callback

$.each(["A", "B"]) { 
  print("Value \($0)")
}
=> ["A", "B"]

$.each(["A", "B"]) { (index, elem) in
  print("\(index) - \(elem)")
}
=> ["0 - A", "1 - B"]

every - `$.every`

Checks if the given callback returns true value for all items in the array.

$.every([1, 2, 3, 4], callback: { $0 < 20 }) 
=> true

$.every([1, 2, 3, 4]) { $0 == 1 } 
=> false

factorial `$.factorial`

Returns factorial of integer

$.factorial(3)
=> 6

$.factorial(0)
=> 1

fetch - `$.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]
$.fetch(arr, 100)
=> nil

$.fetch(arr, 100, orElse: 42)
=> 42

$.fetch(arr, -1)
=> 8

fill - `$.fill`

Fills elements of array with value from start up to, but not including, end. This method mutates array.

var arr = Array<Int>(count: 5, repeatedValue: 1)
$.fill(&arr, withElem: 42)
=> [42, 42, 42, 42, 42]

var arr = Array<Int>(count: 5, repeatedValue: 1)
$.fill(&arr, withElem: 42, startIndex: 1, endIndex: 3)
=> [1, 42, 42, 42, 1]

find - `$.find`

Iterates over elements of an array and returning the first element that the callback returns true for.

$.find([1, 2, 3, 4], callback: { $0 == 2 }) 
=> 2

$.find([1, 2, 3, 4]) { $0 == 10 } 
=> nil

findIndex - `$.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 = $.findIndex(arr) { $0["age"] < 20 }
result 
=> 2

findLastIndex - `$.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 = $.findLastIndex(arr) { $0["age"] > 30 }
result
=> 1

first - `$.first(array: AnyObject[])`

Gets the first element in the array.

$.first([1, 2, 3, 4])
=> 1

$.first([]) 
=> nil

groupBy `$.groupBy`

This method returns a dictionary of values grouped by the value returned by a callback.

$.groupBy([1, 2, 3, 4, 5], callback: {$0 % 2})
=> [0: [2, 4], 1: [1, 3]]

$.groupBy(["strings", "with", "different", lengths"], callback: {$0.characters.count})
=> [7: ["strings", "lengths"], 9: ["different"], 4: ["With"]]

second - `$.second(array: AnyObject[])`

Gets the second element in the array.

$.second([1, 2, 3, 4])
=> 2

$.second([1]) 
=> nil

$.second([])
=> nil

flatMap - `$.flatMap`

Maps a function that converts elements to a list and then concatenates them.

let values = [2, 3, 4, 5, 6, 7]
$.flatMap(values) { [$0, $0] }
=> [2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7]

flatMap - `$.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")
$.flatMap(url) { $0.lastPathComponent }
=> Optional("swift")

Note: This is the same behavior as Optional chaining. The code above translates to

NSURL(string: "https://apple.com/swift/")?.lastPathComponent
=> Optional("swift")

flatten - `$.flatten`

Flattens a nested array of any depth.

$.flatten([[3], 4, 5]) as Int[] 
=> [3, 4, 5]

$.flatten([[3], "Hello", 5]) as NSObject[] 
=> [3, "Hello", 5]

$.flatten([[[3], 4], 5]) as Int[] 
=> [3, 4, 5]

frequencies - `$.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.

$.frequencies(["a", "a", "b", "c", "a", "b"]) 
=> ["a": 3, "b": 2, "c": 1]

$.frequencies([1, 2, 3, 4, 5]) { $0 % 2 == 0 }
=> [false: 3, true: 2]

gcd `$.gcd`

GCD function return greatest common denominator with number passed

$.gcd(3, 10)
=> 1

$.gcd(3, 9)
=> 3

indexOf - `$.indexOf`

Gets the index at which the first occurrence of value is found.

$.indexOf([1, 2, 3, 1, 2, 3], value: 2) 
=> 1

$.indexOf(["A", "B", "C"], value: "B") 
=> 1

$.indexOf([3, 4, 5], value: 5) 
=> 2

$.indexOf([3, 4, 5], value: 3) 
=> 0

$.indexOf([3, 4, 5], value: 2) 
=> nil

initial - `$.initial`

Gets all but the last element or last n elements of an array.

$.initial([3, 4, 5]) 
=> [3, 4]

$.initial([3, 4, 5], numElements: 2) 
=> [3]

intersection - `$.intersection`

Creates an array of unique values present in all provided arrays.

$.intersection([1, 2, 3], [5, 2, 1, 4], [2, 1]) 
=> [1, 2]

it-isIn `$.it<T: Comparable>(i: T, isIn range: Range<T>)`

Returns true if i is in interval or range

$.it("c", isIn: "a"..."z")
=> true

$.it("z", isIn: "a"..<"z")
=> false

$.it(1, isIn: -1.0...10.0)
=> true

last - `$.last`

Gets the last element from the array.

$.last([3, 4, 5]) 
=> 5

lastIndexOf - `$.lastIndexOf`

Gets the index at which the last occurrence of value is found.

$.lastIndexOf([1, 2, 3, 1, 2, 3], value: 2) 
=> 4

lcm `$.lcm`

LCM method return least common multiple with number passed

$.lcm(3, 10)
=> 30

$.lcm(3, 9)
=> 9

rest - `$.rest`

The opposite of initial this method gets all but the first element or first n elements of an array.

$.rest([3, 4, 5]) 
=> [4, 5]

$.rest([3, 4, 5], numElements: 2) 
=> [5]

map - `$.map`

Maps each element to new value based on the map function passed

$.map([1, 2, 3, 4]) { 
  $0 * 2
}
=> [2, 4, 6, 8]

min - `$.min`

Retrieves the minimum value in an array.

$.min([2, 1, 2, 3, 4]) 
=> 1

max - `$.max`

Retrieves the maximum value in an array.

$.max([1, 2, 3, 4, 2, 1]) 
=> 4

pluck - `$.pluck`

Retrieves the value of a specified property from all elements in the array.

let arr = [["age": 20], ["age": 30], ["age": 40]]
$.pluck(arr, value: "age") 
=> [20, 30, 40]

pull - `$.pull`

Removes all provided values from the given array.

$.pull([3, 4, 5, 3, 5], values: 3, 5) 
=> [4]

$.pull([3, 4, 5, 3, 5], values: 4) 
=> [3, 5, 3, 5]

$.pull([3, 4, 5, 3, 5], values: 3, 4, 5) 
=> []

pullAt - `$.pullAt`

Removes all provided values from the given array at the given indices

let arr = [10, 20, 30, 40, 50]
$.pullAt(arr, indices: 1, 2, 3)

range - `$.range`

Creates an array of numbers (positive and/or negative) progressing from start up to but not including end.

$.range(4) 
=> [0, 1, 2, 3]

$.range(from: 1, to: 5) 
=> [1, 2, 3, 4]

$.range(from: 0, to: 20, incrementBy: 5) 
=> [0, 5, 10, 15]

$.range(from: 1, through: 5)
=> [1, 2, 3, 4, 5]

$.range(from: 0, through: 20, incrementBy: 5)
=> [0, 5, 10, 15, 20]

reduce - `$.reduce`

Reduce function that will resolve to one value after performing combine function on all elements

$.reduce([1, 2, 3], initial: 0) { (total, element) in
    total + element
}
=> 6

sample - `$.sample`

Returns a sample item from the array

let arr : Int[] = [2, 1, 2, 3, 4]
$.contains(arr, value: $.sample(arr))
=> true

sequence - `$.sequence`

Creates an array of an arbitrary sequence. Especially useful with builtin ranges.

$.sequence(0..4) 
=> [0, 1, 2, 3]

$.sequence(-2.0..2.0) 
=> [-2.0, -1.0, 0.0, 1.0]

$.sequence((0..20).by(5)) 
=> [0, 5, 10, 15]

$.sequence("abc") 
=> ["a", "b", "c"]

remove - `$.remove`

Removes an element from array.

$.remove(["A", "B", "C", "D"], value: "B")
=> ["A", "C", "D"]

remove - `$.remove`

Removes all elements from an array that the callback returns true.

let result = $.remove([1, 2, 3, 4, 5, 6]) { 
  $0 == 2 || $0 == 3 
}
result
=> [1, 4, 5, 6]

shuffle - `$.shuffle`

Shuffles and returns the new shuffled array

let result = $.shuffle([1, 2, 3, 4, 5, 6])
result
=> [4, 1, 3, 5, 6, 2]

size - `$.size`

Returns size of the array

$.size(["a", "b", "c")
=> 3

sortedIndex - `$.sortedIndex`

Gives the smallest index at which a value should be inserted into a given the array is sorted.

$.sortedIndex([3, 4, 6, 10], value: 5)
=> 2

$.sortedIndex([10, 20, 30, 50], value: 40)
=> 3

transpose - `$.transpose`

Creates a tranposed matrix.

$.transpose([[1, 2, 3], [4, 5, 6]])
=> [[1, 4], [2, 5], [3, 6]]

union - `$.union`

Creates an array of unique values, in order, of the provided arrays.

$.union([1, 2, 3], [5, 2, 1, 4], [2, 1]) 
=> [1, 2, 3, 5, 4]

merge - `$.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 = $.merge(arr, arr2, arr3)
result
=> [1, 5, 2, 4, 5, 6]

uniq - `$.uniq`

Creates a duplicate-value-free version of an array.

$.uniq([1, 2, 1, 3, 1])
=> [1, 2, 3]

$.uniq([1, 2.5, 3, 1.5, 2, 3.5]) {
  floor($0)
}
=> [1, 2.5, 3]

without - `$.without`

Creates an array excluding all provided values.

$.without([3, 4, 5, 3, 5], values: 3, 5)
=> [4]

$.without([3, 4, 5, 3, 5], values: 4)
=> [3, 5, 3, 5]

$.without([3, 4, 5, 3, 5], values: 3, 4, 5)
=> []

xor - `$.xor`

Creates an array that is the symmetric difference of the provided arrays.

$.xor([1, 2, 3], [5, 2, 1, 4])
=> [3, 4, 5]

zip - `$.zip`

Creates an array of grouped elements, the first of which contains the first elements of the given arrays.

$.zip(["fred", "barney"], [30, 40], [true, false]) as [NSObject] 
=> [["fred", 30, true], ["barney", 40, false]]

zipObject - `$.zipObject`

Creates an object composed from arrays of keys and values.

$.zipObject(["fred", "barney"], values: [30, 40])
=> ["fred": 30, "barney": 40]

partition - `$.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]
$.partition(arr, n: 2)
=> [[1, 2], [3, 4]]

$.partition(arr, n: 4, step: 1)
=> [[1, 2, 3, 4], [2, 3, 4, 5]]

$.partition(arr, n: 4, step: 1, pad: nil)
=> [[1, 2, 3, 4], [2, 3, 4, 5], [3, 4, 5]]

$.partition(arr, n: 4, step: 1, pad: [6, 7, 8])
=> [[1, 2, 3, 4], [2, 3, 4, 5], [3, 4, 5, 6]]

partitionAll - `$.partitionAll`

Produces an array of arrays, each containing n elements, each offset by step. Continues after a partition is less than n length.

$.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 - `$.partitionBy`

Applies a function to each element in array, splitting it each time the function returns a new value.

$.partitionBy([1, 2, 3, 4, 5]) { $0 % 2 == 0 }
=> [[1], [2, 4], [3, 5], [6]]

$.partitionBy([1, 7, 3, 6, 10, 12]) { $0 % 3 }
=> [[1, 7], [3, 6], [10], [12]]

Dictionary

keys - `$.keys`

Creates an array of keys given a dictionary.

$.keys(["Dog": 1, "Cat": 2])
=> ["Dog", "Cat"]

values - `$.values`

Creates an array of values given a dictionary

$.values(["Dog": 1, "Cat": 2])
=> [1, 2]

merge - `$.merge`

Merges all of the dictionaries together and the latter dictionary overrides the value at a given key

let dict: Dictionary<String, Int> = ["Dog": 1, "Cat": 2]
let dict2: Dictionary<String, Int> = ["Cow": 3]
let dict3: Dictionary<String, Int> = ["Sheep": 4]
$.merge(dict, dict2, dict3)
=> ["Dog": 1, "Cat": 2, "Cow": 3, "Sheep": 4]

pick - `$.pick`

Creates a shallow clone of a dictionary composed of the specified keys.

$.pick(["Dog": 1, "Cat": 2, "Cow": 3], keys: "Dog", "Cow")
=> ["Dog": 1, "Cow": 3]

omit - `$.omit`

Creates a shallow clone of a dictionary excluding the specified keys.

$.omit(["Dog": 1, "Cat": 2, "Cow": 3, "Sheep": 4], keys: "Cat", "Dog")
=> ["Cow": 3, "Sheep": 4]

Object

tap - `$.tap`

Invokes interceptor with the object and then returns object.

var beatle = Car(name: "Fusca")
$.tap(beatle, {$0.name = "Beatle"}).color = "Blue"

Function

after - `$.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 = false
var completeCallback = $.after(saves.count) {
   isDone = true
}
for elem in saves {
   asyncSave(completeCallback)
}
isDone 
=> true

bind - `$.bind`

Creates a function that, when called, invokes func with the binding of arguments provided.

var helloWorldFunc = $.bind({(T...) in
  T[0] + " " + T[1] + " from " + T[2] 
}, "Hello", "World", "Swift")
helloWorldFunc() 
=> "Hello World from Swift"

helloWorldFunc = $.bind({ $0 + " World" }, "Hello")
helloWorldFunc()
=> "Hello World"

helloWorldFunc = $.bind({ $0 + $1 + " World" }, "Hello ", "Great")
helloWorldFunc()
=> "Hello Great World"

compose - `$.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 input

let double = { (params: Int...) -> [Int] in
  return $.map(params) { $0 * 2 }
}
let subtractTen = { (params: Int...) -> [Int] in
  return $.map(params) { $0 - 10 }
}
let doubleSubtractTen = $.compose(double, subtractTen)
doubleSubtractTen(5, 6, 7)
=> [0, 2, 4]

let f = $.compose({ (arr: [Int]) -> [Int] in
  $.map(arr) { $0 + 1 }
}, { (arr: [Int]) -> [Int] in
  $.map(arr) { $0 * 2 }
})
f([1, 2])
=> [4, 6]

curry - `$.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 = $.curry(adder)
let addTenAnd = curriedAdder(10)
let addThirtyAnd = addTenAnd(20)
addThirtyAnd(1)
=> 31

addThirtyAnd(50)
=> 80

addTenAnd(10)(10)
=> 30

id - `$.id`

The identify function which simply returns the argument its given.

$.id("Hello World from Swift")
=> "Hello World from Swift"

memoize - `$.memoize`

Returns a memoized function to improve performance by caching recursive function values.

var times = 0 // to test memoization

let fibMemo = $.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
=> 6

times = 0
let y = fibMemo(5)
times
=> 0

times = 0
let z = fibMemo(6)
times
=> 1

noop - `$.noop`

A no-operation function.

$.noop() 
=> nil

now - `$.now`

Gets the number of seconds that have elapsed since the Unix epoch (1 January 1970 00:00:00 UTC).

$.now() 
=> 1431911564.292577

once - `$.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 = $.once(createConfig)
getConfig()
=> ["App ID": "1", "URL": "https://someurl"]

getConfig()
=> ["App ID": "1", "URL": "https://someurl"]

partial - `$.partial`

Creates a function that, when called, invokes func with any additional partial arguments prepended to those provided to the new function.

let partialFunc = $.partial({(T...) in 
  T[0] + " " + T[1] + " from " + T[2] 
}, "Hello")
partialFunc("World", "Swift") 
=> "Hello World from Swift"

times - `$.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 = $.bind({ (names: String...) -> String in
   let people = $.join(names, separator: " from ")
   return "Hello \(people)"
   }, "Ankur", "Swift")
$.times(2, function: fun) as String[] 
=> ["Hello Ankur from Swift", "Hello Ankur from Swift"]

Chaining

$.chain(...)

`any`

Returns true if callback function returns true for at least one element in the array

var chain = $.chain([1, 2, 3])
chain.any({ ($0 as Int) < 2 })
=> true

`all`

Returns true if callback function returns true for all elements in the array

var chain = $.chain([1, 2, 3])
chain.all({ ($0 as Int) < 10 })
=> true

`each`

Passes each element value to the callback function

var chain = $.chain(["Hello", "World"])
var strBuilder = ""
chain.each({ strBuilder += ($0 as String) }).value
strBuilder
=> "HelloWorld"

`filter`

Filters the arrary to elements for which the callback function returns true

var chain = $.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 chain

var chain = $.chain([1, 2, 3, 4])
chain.first()
=> 1

`second`

Returns the second element in the array and terminates the chain

var chain = $.chain([1, 2, 3, 4])
chain.second()
=> 2

`third`

Returns the third element in the array and terminates the chain

var chain = $.chain([1, 2, 3, 4])
chain.third()
=> 3

`flatten`

Flattens a nested array of any depth.

var chain = $.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 = $.chain([1, 2, 3, 4])
chain.initial(2).value
=> [1, 2]

`map`

Maps each element to the new value returned in the callback function

var chain = $.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 chain

var chain = $.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 = $.chain([1, 2, 3, 4, 5, 6, 7])
chain.slice(2, end: 4).value
=> [3, 4]

`value`

Returns the value after evaluating all callbacks

var chain = $.chain([1, 2, 3, 4, 5, 6, 7])
chain.value
=> [1, 2, 3, 4, 5, 6, 7]

Chaining more than one method

$.chain([[1, 2], 3, [[4], 5]])
  .initial()
  .flatten()
  .first()
=> 1

$.chain([1, 2, 3, 4, 5])
  .filter { $0 % 1 == 0 }
  .map { $0 * 2 }
  .all {$0 < 10}
=> false

$.chain([1, 2, 3, 4, 5])
  .map({ $0 * 2 })
  .flatten()
  .initial(2).value
=> [2, 4, 6]

Cent Usage

Array Extensions

`<< elem: Element -> [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 << 4
=> [1, 2, 3, 4]
array << [5, 6]
=> [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 elem

let 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 index

let array = ["foo", "spam", "bar", "eggs"]
array.each { (index, elem)
  print("\(index) - \(elem)")
}
=> ["foo", "spam", "bar", "eggs"]

`cycle<U>(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 following
123123

[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<T: Equatable>(value: T) -> Int`

Gets the index at which the first occurrence of value is found.

let array = ["foo", "spam", "bar", "eggs"]
array.indexOf("spam")
=> 1
array.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)
=> nil

arr.fetch(100, orElse: 42)
=> 42

arr.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 index

let 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: Comparable>() -> T?`

Retrieves the minimum value in an array.

let min = [ 0, 1, 2 ].min()
=> 0

`max<T: Comparable>() -> T?`

Retrieves the maximum value in an array.

let max = [ 0, 1, 2].max()
=> 2

`remove<T: Equatable>(value: T) -> T?`

Remove element from array

var arr = ["A", "B", "C", "D", "E"]
arr.remove("B")
=> ["A", "C", "D", "E"]

`contains<T:Equatable>(value: T) -> Bool`

Checks if a given value is present in the array.

var arr = ["A", "B", "C", "D", "E"]
arr.contains("C")
=> true
arr.contains("Z")
=> false

Character Extensions

`"A".description -> String`

Get string description of Character

let ch: Character = "A"
let str = ch.description
=> "A"

`"A".ord -> Int`

Get int representation of character

Character("A").ord
=> 65

Date Extensions

`Date.from(#year: Int, month: Int, day: Int) -> NSDate`

Returns a new Date given the year month and day

let 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 Date

let 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 timestamp

let currentUnix = Date.unix()
=> 1,388,552,400.0

var 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<K, V>(dictionaries: Dictionary<K, V>...)`

Merges the dictionary with dictionaries passed. The latter dictionaries will override values of the keys that are already set

var 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 index

5.times { print("Na") } 
=> "NaNaNaNaNa"

`times (function: () -> ())`

Invoke a callback n times

5.times { (a: Int) -> () in print("\(a) ") } 
=> 0 1 2 3 4

`char -> Character`

Get ASCII character from integer

65.char
=> "A"

`isEven`

Check if int is even

2.isEven
=> true

1.isEven
=> false

`isOdd`

Check if int is odd

3.isOdd
=> true

2.isOdd
=> false

`digits() -> [Int]`

Splits the int into array of digits

4208.digits()
=> [4, 2, 0, 8]

`lcm() -> Int`

LCM method return least common multiple with number passed

3.lcm(10)
=> 30

3.lcm(9)
=> 9

`gcd() -> Int`

GCD method return greatest common denominator with number passed

3.gcd(10)
=> 1

3.gcd(9)
=> 3

`random() -> Int`

Returns random number from 0 upto but not including value of integer

3.random()
=> 2

3.random()
=> 1

`factorial() -> Int`

Returns factorial of integer

3.factorial()
=> 6

0.factorial()
=> 1

`isIn(interval) -> Bool`

Returns true if i is in interval or range

5.isIn(1...10)
=> true

10.isIn(1..<10)
=> false

`next() -> Int`

Get the next int

10.next()
=> 11

`prev() -> Int`

Get the previous int

10.prev()
=> 9

`upTo(limit: Int, callback: () -> ())`

Invoke the callback from int up to and including limit

3.upTo(5) {
  print("Hi")
}
Prints "HiHiHi"

`downTo(limit: Int, callback: () -> ())`

Invoke the callback from int down to and including limit

3.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 subscript

let proj = "Dollar and Cent"
proj["^.+[^and Cent]"]
=> {Some: "Dollar"}

`[r: Range<Int>] -> String`

Get substring using subscript notation and by passing a range

"Hello World"[0..<5] == "Hello" 
=> 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 spaces

let leadingSpace = "  Hello"
leadingSpace.lstrip()
=> "Hello"

`rstrip() -> String`

Get string without trailing spaces

let trailingSpace = "Hello   "
trailingSpace.rstrip()
=> "Hello"

`strip() -> String`

Get string without leading or trailing spaces

let spaces = "   Hello   "
spaces.strip()
=> "Hello"

Regex

`init`

Init with regex pattern as string

Regex.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) -> Bool`

let re = Regex.init("^Hello.World$")
re.test("Hello World")
=> true

re.test("Str")
=> false

`escapeStr(str: String) -> String`

Escape string with regex characters

Regex.escape("Hello.World")
=> "Hello\.World"

Range Extensions

equals - `==`

Check the equality of two ranges

(1...5) == (1...5) 
=> true

(1..<5) == (1...5) 
=> 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

Name		Name	Last commit message	Last commit date
Latest commit History 610 Commits
Dollar.xcodeproj		Dollar.xcodeproj
Sources		Sources
Tests		Tests
scripts		scripts
.gitignore		.gitignore
.hound.yml		.hound.yml
.swift-sample		.swift-sample
.swift-version		.swift-version
.swiftlint.yml		.swiftlint.yml
.travis.yml		.travis.yml
CODE_OF_CONDUCT.md		CODE_OF_CONDUCT.md
CONTRIBUTING.md		CONTRIBUTING.md
Dollar.podspec		Dollar.podspec
LICENSE		LICENSE
Package.swift		Package.swift
README.md		README.md

License

Patrickuang/Dollar

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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 - $.at

chunk - $.chunk

compact - $.compact

contains - $.contains

cycle - $.cycle

delay - $.delay

debounce - $.debounce

difference - $.difference

each - $.each

every - $.every

factorial $.factorial

fetch - $.fetch

fill - $.fill

find - $.find

findIndex - $.findIndex

findLastIndex - $.findLastIndex

first - $.first(array: AnyObject[])

groupBy $.groupBy

second - $.second(array: AnyObject[])

flatMap - $.flatMap

flatMap - $.flatMap

flatten - $.flatten

frequencies - $.frequencies

gcd $.gcd

indexOf - $.indexOf

initial - $.initial

intersection - $.intersection

it-isIn $.it<T: Comparable>(i: T, isIn range: Range<T>)

last - $.last

lastIndexOf - $.lastIndexOf

lcm $.lcm

rest - $.rest

map - $.map

min - $.min

max - $.max

pluck - $.pluck

pull - $.pull

pullAt - $.pullAt

range - $.range

reduce - $.reduce

sample - $.sample

sequence - $.sequence

remove - $.remove

remove - $.remove

shuffle - $.shuffle

size - $.size

sortedIndex - $.sortedIndex

transpose - $.transpose

union - $.union

merge - $.merge

uniq - $.uniq

without - $.without

xor - $.xor

zip - $.zip

zipObject - $.zipObject

partition - $.partition

partitionAll - $.partitionAll

partitionBy - $.partitionBy

Dictionary

keys - $.keys

values - $.values

merge - $.merge

pick - $.pick

Using `git submodule`

at - `$.at`

chunk - `$.chunk`

compact - `$.compact`

contains - `$.contains`

cycle - `$.cycle`

delay - `$.delay`

debounce - `$.debounce`

difference - `$.difference`

each - `$.each`

every - `$.every`

factorial `$.factorial`

fetch - `$.fetch`

fill - `$.fill`

find - `$.find`

findIndex - `$.findIndex`

findLastIndex - `$.findLastIndex`

first - `$.first(array: AnyObject[])`

groupBy `$.groupBy`

second - `$.second(array: AnyObject[])`

flatMap - `$.flatMap`

flatMap - `$.flatMap`

flatten - `$.flatten`

frequencies - `$.frequencies`

gcd `$.gcd`

indexOf - `$.indexOf`

initial - `$.initial`

intersection - `$.intersection`

it-isIn `$.it<T: Comparable>(i: T, isIn range: Range<T>)`

last - `$.last`

lastIndexOf - `$.lastIndexOf`

lcm `$.lcm`

rest - `$.rest`

map - `$.map`

min - `$.min`

max - `$.max`

pluck - `$.pluck`

pull - `$.pull`

pullAt - `$.pullAt`

range - `$.range`

reduce - `$.reduce`

sample - `$.sample`

sequence - `$.sequence`

remove - `$.remove`

remove - `$.remove`

shuffle - `$.shuffle`

size - `$.size`

sortedIndex - `$.sortedIndex`

transpose - `$.transpose`

union - `$.union`

merge - `$.merge`

uniq - `$.uniq`

without - `$.without`

xor - `$.xor`

zip - `$.zip`

zipObject - `$.zipObject`

partition - `$.partition`

partitionAll - `$.partitionAll`

partitionBy - `$.partitionBy`

keys - `$.keys`

values - `$.values`

merge - `$.merge`

pick - `$.pick`

omit - `$.omit`

tap - `$.tap`

after - `$.after`

bind - `$.bind`

compose - `$.compose`

curry - `$.curry`

id - `$.id`

memoize - `$.memoize`

noop - `$.noop`

now - `$.now`

once - `$.once`

partial - `$.partial`

times - `$.times`

`any`

`all`

`each`

`filter`