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iOS Swift Basics (retired) Collections What is a Dictionary?

Jacob Tucker
Jacob Tucker
512 Points

why doesnt the following statement work let ukCurrency = currencies.removeValueForKey ("UK")

assuming first line is correct which it is


1 Answer

Stone Preston
Stone Preston
42,016 Points

you misinterpreted what the task is asking you to do.

task 2 states: Assign the value for key "UK" to a constant named ukCurrency.

you dont remove the value assigned to the key "UK", you assign the value of that key to a new constant, whilst keeping the dictionary the same (you dont want to remove any keys/values or anything like that)

the swift eBook states:

You access and modify a dictionary through its methods and properties, or by using subscript syntax

subscript syntax consists of the name of the dictionary followed by a pair of square brackets with the key inside:


the above code returns the value for the key "someKey" in the dictionary named someDictionary

so to assign the value for the key "UK" to a constant named ukCurrency you would use

let currencies = [ "US": "Dollar", "UK": "Pound", "JP": "Yen"]

let ukCurrency = currencies["UK"] // ukCurrency now has a value of "Pound"