Payal Gupta


Random Numbers API in Swift 4.2

Random is Good…🎳

With the release of Swift 4.2, Apple introduced a new random API SE-0202 in swift’s standard library.

Let’s look at the details on how we can use this API for different use-cases.

1. Random number from the given Range

A random(in:) method is provided for each numeric data type, i.e. Int, UInt, Float, Double and also for Bool data type.

random(in:) — Returns a random value within the specified range.

Int.random(in: -10...10)   //-6 : Random number in range -10 to 10

Similarly, we can get a random number for other numeric data types too.

Int.random(in: Int.min...Int.max)   //5995714053130751044
UInt.random(in: 0..<10) //8
Double.random(in: 0...10) //0.4317509841160627
Float.random(in: 0...1) //0.05182791
Bool.random() //false

2. Random element from a Collection

Getting a random element from a collection i.e. array, dictionary or sets, is something we come across very frequently.

randomElement()— Returns a random element of the collection.

This method is available on each collection type in swift.

var arr = [1, 2, 4]
arr.randomElement() //Returns an element from arr randomly
var dict = ["one": 1, "two": 2, "three": 3]
dict.randomElement() //Returns an element from dict randomly
(0...10).randomElement() //Returns an element from range randomly

In case the collection is empty, the randomElement() returns nil.

3. Shuffling the elements of a Collection

Elements in collection can be shuffled using shuffled() or shuffle() methods.

shuffle() — Shuffles the collection in place.

shuffled() — Returns the elements of the sequence, shuffled.

These methods are also available on each collection type in swift.

var arr = [1, 2, 4]
arr.shuffled() //returns a new array - [4, 2, 1]
arr.shuffle() //shuffles elements in arr itself - [4, 1, 2]
(0...10).shuffled()   //[3, 2, 5, 7, 10, 9, 1, 6, 8, 4, 0]

Further reading

Don’t forget to read my other articles:

  1. Everything about Codable in Swift 4
  2. Everything you’ve always wanted to know about notifications in iOS
  3. Deep copy vs. shallow copy — and how you can use them in Swift
  4. Coding for iOS 11: How to drag & drop into collections & tables
  5. All you need to know about Today Extensions (Widget) in iOS 10
  6. UICollectionViewCell selection made easy..!!

Feel free to leave comments in case you have any questions.

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