CODEWITHSUNDEEP
arraysswift
Stefano Gerli
Stefano Gerli

Reputation: 23

Not able to set value of a dictionary inside a array [Swift]

I am trying to set the value of a dictionary inside a array in swift but I get an error.
It says Cannot pass immutable value of type '[Dictionary]' to mutating binary operator '+='

My code is the following:
// Declare the array var numbersArray:[Dictionary] = [Dictionary<String, Any>]()

... more code ...

func createArray() {
    for var iteration = 0; iteration < 75; iteration++ {
        //Add numbers to the array
        // May be used to set column
        var column:String
        switch iteration {
        case 0...14:
            column = "B"
            numbersArray += [["Randomized" : false, "Column" : "B", "Origin" : 0]]
        case 15...29:
            column = "I"
            numbersArray += [["Randomized" : false, "Column" : "I", "Origin" : 0]]
        case 30...44:
            column = "N"
            numbersArray += [["Randomized" : false, "Column" : "N", "Origin" : 0]]
        case 45...59:
            column = "G"
            numbersArray += [["Randomized" : false, "Column" : "G", "Origin" : 0]]
        case 60...74:
            column = "O"
            numbersArray += [["Randomized" : false, "Column" : "O", "Origin" : 0]]
        default:
            column = "Out Of Bounds"
            numbersArray += [["Randomized" : false, "Column" : "Out Of Bounds", "Origin" : 0]]
        }
        // numbersArray1 += [["Randomized" : false, "Column" : String(column), "Origin" : 0]]

    }
}

Any Idea?
Note: This worked perfectly in the playground.

Upvotes: 0

Views: 126

Answers (2)

0x416e746f6e
0x416e746f6e

Reputation: 10136

I think there are 2 problems.

First of all, you declare numbersArray to be an array of generic dictionaries, which is something that makes my XCode to crash. The following approach works better for me:

var numbersArray = [[String: Any]]()

Secondly, I guess createArray is a method in a struct, in which case you have to use mutating in its declaration to allow it to modify struct's properties.

mutating func createArray() {
    // ...
}

Upvotes: 0

Icaro
Icaro

Reputation: 14845

You can't use += for arrays of not compatible items (where the type can change), you need append the value to the array like so:

var numbersArray = [Dictionary<String, Any>]() 
numbersArray.append(["Randomized" : false, "Column" : "B", "Origin" : 0])

You would be able to use += if you had an array of Strings or Int's

var numbersArray = [String]() 
NumbersArray += ["I am always a string"]

More details about collections at this apple documentation

Upvotes: 1

Related Questions