Swift Dictionary Get Key for Values

Question

I have a dictionary defined as:

let drinks = [String:[String]]()

drinks = ["Soft Drinks": ["Cocoa-Cola", "Mountain Dew", "Sprite"], 
"Juice" :["Orange", "Apple", "Grape"]]

How can I get the key, for a given value.

let key = (drinks as NSDictionary).allKeysForObject("Orange") as! String
print(key)
//Returns an empty Array. Should return "Juice"

Answer 1

func findKeyForValue(value: String, dictionary: [String: [String]]) ->String?
{
    for (key, array) in dictionary
    {
        if (array.contains(value))
        {
            return key
        }
    }

    return nil
}

Call the above function which will return an optional String?

let drinks = ["Soft Drinks": ["Cocoa-Cola", "Mountain Dew", "Sprite"],
        "Juice" :["Orange", "Apple", "Grape"]]

print(self.findKeyForValue("Orange", dictionary: drinks))

This function will return only the first key of the array which has the value passed.