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Adding values ​​to a dictionary with quick

I have this dictionary:

var dict = ["cola" : 10, "fanta" : 12, "sprite" : 8]

and I want to add values, for example to get the result as 30, how can I do that? In other words, how can I only add numbers and not words?

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3 answers


As described in the docs here. You access and modify the dictionary through its methods and properties, or through substring syntax. Read the document.

var dict = ["cola" : 10, "fanta" : 12, "sprite" : 8]

To access a value in a dictionary, you can use the substring syntax:

if let cola = dict["cola"] as? Int { // to read the value
    // Do something 
}
dict["cola"] = 30 // to change the value  
dict["pepsi"] = 25 // to add a new entry to your dictionary
dict["fanta"] = nil // to delete the fanta entry.


to read all the meaning in your dictionary

var sum = 0
for (drinkName, drinkValue) in dict {
    println("\(drinkName): \(drinkValue)")
    sum += drinkValue
}

or you can

var sum = 0
for drinkValue in dict.values {
   sum += drinkValue
}
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Since the answer is accepted and not very good, I will have to abandon the Socratic method and show a more thematic way of answering this question.

Given your dictionary:

var dict = ["cola" : 10, "fanta" : 12, "sprite" : 8]

You get the sum by creating an array of dict.values

and decreasing them

let sum = Array(dict.values).reduce(0, +)


Or you can use a simple Reduce form that doesn't require the initial creation of the array:

let sum = reduce(dict.values, 0, +)

Or a more modern version, since it reduce

is defined on an array

let sum = dict.values.reduce(0, +)
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The accepted answer does not use the power of the swift

and the answer that does this is out of date.

Simplest updated solution:

 let valuesSum = dict.values.reduce(0, +)

start from zero and sum the values ​​of all elements

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