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iOS Functions in Swift Adding Power to Functions Returning Complex Values

Ruben Corvalan
Ruben Corvalan
782 Points
Posted by Ruben Corvalan
Ruben Corvalan
782 Points

Using dictionary with an array.

I would like to access the values of an array inside a Dictionary using a tuple. In this particular case I would like to access the value of the array for the key "Ruben" by assigning the array value of "Ruben" to the tuple and then prince the array values.

Here it is.

var dictionary: [String:Double]

dictionary = ["Ruben": [1952.45, 56.87], "Peter": [456.34, 98.98]]

let tuple: (Double, Double)

tuple = dictionary["Ruben"]

The error at the last line is "Cannot assign value of type '[Double]?' to type '(Double, Double)'"

I think I am misunderstanding how can I assign a dictionary array to a tuple.

Please help.

Thanks.

2 Answers

Dhanish Gajjar
Dhanish Gajjar
20,185 Points
Dhanish Gajjar
Dhanish Gajjar
20,185 Points

The way that the dictionary is defined is incorrect. Since the value in your <key, Value> Pair of dictionary is an Array of Doubles, the correct definition would be

var dictionary: [String: [Double]]
dictionary = ["Ruben": [1952.45, 56.87], "Peter": [456.34, 98.98]]

To access the value of any given key, the implementation is simple

let value = dictionary["Ruben"]

Hope it helps.

Ruben Corvalan
Ruben Corvalan
782 Points
Ruben Corvalan
Ruben Corvalan
782 Points

Great, thanks. And how can I access a single value of the available values inside the array? Examples, how can I access the double 56.87 in the key "Ruben"? Thanks.

Dhanish Gajjar
Dhanish Gajjar
20,185 Points
Dhanish Gajjar
Dhanish Gajjar
20,185 Points

Ruben Corvalan If you haven't finished Enumerations and Optionals course, then it will be confusing, I suggest you go through videos in the courses, wait till you get to that point.

There is a concept of optional binding that you will learn in Enumerations and Optionals course.

let dictionary = ["Ruben": [1952.45, 56.87], "Peter": [456.34, 98.98]]

if let value = dictionary["Ruben"] {
    let singleValue = value[0]
}

All it says is we are assigning the dictionary value from <key, value> pair of the dictionary to a constant named value. So now the Array of Doubles is assigned to that constant. We can now used value[0] to retrieve the first value in the array and value[1] to retrieve the second value.