I got the following code:
var myDic = [String: Customer]()
let s1 = Customer("nameee", "email1")
let s2 = Customer("nameee2", "email2")
let s3 = Customer("nameee3", "email3")
myDic[s1.name] = s1
myDic[s2.name] = s2
myDic[s3.name] = s3
How can I select a random element from the dictionary? I think I should use arc4random_uniform but couldn't find any documentation on it.
If you want to get a random key from a dictionary, you can use the dictionary keys() function instead. If you want to get a random key/value pair from a dictionary, you can use the dictionary items() function.
In Swift, we can get a random element from an array by using randomELement() . If the array is empty, nil is returned.
Swift – Check if Specific Key is Present in Dictionary To check if a specific key is present in a Swift dictionary, check if the corresponding value is nil or not. If myDictionary[key] != nil returns true, the key is present in this dictionary, else the key is not there.
You have to cast some things around, but this seems to work.
var dict:[String:Int] = ["A":123, "B": 234, "C": 345]
let index: Int = Int(arc4random_uniform(UInt32(dict.count)))
let randomVal = Array(dict.values)[index] # 123 or 234 or 345
Basically, generate a random index value between zero and the total item count. Get the values of the dictionary as an array and then fetch the random index.
You could even wrap that in an extension for easy access.
Swift 4.2+ (Xcode 10+) introduces two simple possibilities.
Either randomElement:
let randomVal = myDict.values.randomElement()
Or randomElement:
let randomVal = myDict.randomElement().value
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