CODEWITHSUNDEEP
iosmacosswift
davecom
davecom

Reputation: 1498

Why can't I subscript a Dictionary<String, Int> with a String?

I have a dictionary of type Dictionary<String, Int> and I'm trying to subscript it with a String. I get the error Cannot subscript a value of type 'Dictionary<String, Int>' with an index of type 'String'

Here is the whole method. I am running Swift 1.2 (Xcode 6.4), but I have also tried it and the same error occurs in Swift 2.0 (Xcode 7b4).

Here is the whole method:

override func isSatisfied<String, Int>(assignment: Dictionary<String, Int>) -> Bool {
        // if all variables have been assigned, check if it adds up correctly
        if assignment.count == variables.count {
            if let s = assignment["S"], e = assignment["E"], n = assignment["N"], d = assignment["D"], m = assignment["M"], o = assignment["O"], r = assignment["R"], y = assignment["Y"] {
                let send: Int = s * Int(1000) + e * Int(100) + n * Int(10) + d
                let more: Int = m * Int(1000) + o * Int(100) + r * Int(10) + e
                let money: Int = m * 10000 + o * 1000 + n * 100 + e * 10 + y
                if (send + more) == money {
                    return true;
                } else {
                    return false;
                }
            } else {
                return false
            }
        }

        // until we have all of the variables assigned, the assignment is valid
        return true
    }

The problem line is if let s = assignment["S"]

Also here is the sourcecode repository: https://github.com/davecom/SwiftCSP

And here is the specific file: https://github.com/davecom/SwiftCSP/blob/master/SwiftCSP/SwiftCSPTests/SendMoreMoneyTests.swift

Upvotes: 0

Views: 323

Answers (1)

Airspeed Velocity
Airspeed Velocity

Reputation: 40965

The problem lies here:

func isSatisfied<String, Int>(assignment: Dictionary<String, Int>) -> Bool {
                 ^===    ^===

You have defined this function as generic, with two placeholders called String and Int. These will mask the regular types. Delete them, as this probably isn’t what you want.

It’s usually easier, when something strange like this happens, to reduce the case down to just show the problem. I didn’t spot what was wrong until I tried trimming your function down to basically this:

enter image description here

(p.s. [String:Int] is shorthand for Dictionary<String,Int>)

Upvotes: 3

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