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

Posted by Saeed Rehman
Saeed Rehman
455 Points

Assign the value for key "UK" to a constant named ukCurrency

I am trying to assign the UK value to a constant name ukCurrency. I have typed the following and it is showing as an error. Please help.

let currencies = [ "US" : "Dollar", "UK" : "Pound", "JP" : "Yen" ] let ukCurrency = currencies.removeValueForKey("UK")

dictionaries.swift 
let currencies = [ "US" : "Dollar", "UK" : "Pound", "JP" : "Yen" ]
let ukCurrency = currencies.removeValueForKey("UK")

3 Answers

Robin Malhotra
Robin Malhotra
14,883 Points

Shouldn't it simply be

let currencies = [ "US" : "Dollar", "UK" : "Pound", "JP" : "Yen" ]
let ukCurrency = currencies["UK"]
Saeed Rehman
Saeed Rehman
455 Points

thanks

Robin Malhotra
Robin Malhotra
14,883 Points

Not a problem. Do consider upvoting my answer, in case other people have similar problems.

Saeed Rehman
Saeed Rehman
455 Points
Saeed Rehman
Saeed Rehman
455 Points

Hi Robin

Thanks for your support, but I have a further question. In the video Amit mentions in order to remove the value for the key, you need to type currencies.removeValueForKey("UK"), so that is why i used it. Not sure why that didn't work.

let ukCurrency = currencies.removeValueForKey("UK")

Robin Malhotra
Robin Malhotra
14,883 Points

That's because you declared currencies with let ,thereby making it a constant. Constants are immutable, i.e, they cannot be modified. So, when you tried to modify the constant dictionary currencies, the compiler threw up an error.

Saeed Rehman
Saeed Rehman
455 Points
Saeed Rehman
Saeed Rehman
455 Points

Thank you again