Object from Array of Dictionaries into an Array

Question

If I have an array of dictionaries in my NSUserDefaults:

["name":"John", "birthplace":"New York"]
["name":"Eric", "birthplace":"London"]
["name":"Sven", "birthplace":"Stockholm"]
["name":"Pierre", "birthplace":"Paris"]

What is the simplest way to get all the names into an array like this

John, Eric, Sven , Pierre

Ozgur Vatansever · Accepted Answer · 2016-10-14 21:36:41Z

3

First off, you should get the array from user defaults in correct type which is [[String: String]]:

let defaults = NSUserDefaults.standardUserDefaults()
if let peopleArray = defaults.arrayForKey("people") as? [[String: String]] {
  ...
}

Then you can use flatMap (or map if you are sure each dictionary has the key name) to extract the names:

peopleArray.flatMap { $0["name"] }

edited Oct 14, 2016 at 21:36

answered Oct 4, 2016 at 10:50

Ozgur Vatansever

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3 Comments

cannyboy Over a year ago

updated question. how would I get this array out of NSUserDefaults?

cannyboy Over a year ago

yes, they are saved with something like defaults.setObject([["name":"John", "birthplace":"New York"],["name":"Eric", "birthplace":"London"]], forKey: "people")

cannyboy Over a year ago

If I do var peopleArray = defaults.arrayForKey("people") then the flatMap code produces Cannot subscript a value of type '[AnyObject]' with an index of type 'String' (Swift 2.x)

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