Cannot convert String to Double in Swift

Question

I have a dictionary as a response from server:

{ 
  "gross_price" = "6.00";
  "gross_price_total" = "6.00";
  "guests_count" = 1;
}

Then I try:

 let x = dictionary["gross_price_total"] as? Double
 let y = dictionary["gross_price_total"]!
 println("result: \(x) \(y)")

As an output I get:

result: nil 6.00

Why? Is it not a Double?

It results that my final code doesn't work:

if let grossPriceTotal = dictionary["gross_price_total"] as? Double {
    println("final result: \(grossPriceTotal)")
}

`"6.00"` is a string, not a number. And if you search for "Swift string to double" then you should find some answers, some are already in the "Related" section ... — Martin R, Apr 28 '15 at 12:44

score 2 · Answer 1 · answered Apr 28 '15 at 12:45

2

This should let you going:

let x = (dictionary["gross_price_total"] as NSString).doubleValue

answered Apr 28 '15 at 12:45

Miknash

7,888
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score 1 · Answer 2 · answered Apr 28 '15 at 12:49

1

You can create an extension where you can initialize your Double with a String. But you have to use the NSString-method doubleValue:

extension Double{
    init(string:String){
        self = (string as NSString).doubleValue
    }
}

let x = Double(string: dictionary["gross_price_total"])

answered Apr 28 '15 at 12:49

Christian

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1

Upvote for a creative way of using the exentions – milo526 Apr 28 '15 at 12:57

Cannot convert String to Double in Swift

2 Answers2

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