Swift, Convert String To Double Error

Question

i wrote a code to convert string to double but gives error :

Cannot convert the expression's type 'Double' to type 'NSString'

and my code is :

var first = previewLable.text
var second = label1.text

var number1: Double = (first as NSString).doubleValue
var number2: Double = (second as NSString).doubleValue

what i have to do to fix this error ???

Thanks

Please use "label", not "lable". – gnasher729 Jul 07 '15 at 12:14 — gnasher729, Jul 07 '15 at 12:14
oops :D , Sorry , Thanks – Ali Sheikhi Jul 07 '15 at 12:16 — Ali Sheikhi, Jul 07 '15 at 12:16

score 13 · Answer 1 · answered Jul 07 '15 at 13:35

13

Also if you're in Swift 2 you can use

Double("3.141592")

which gives an Optional Double, depending on whether it could be parsed

Double("hi")

would give nil

answered Jul 07 '15 at 13:35

Kametrixom

14,673
7
45
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score 2 · Accepted Answer · edited May 23 '17 at 12:13

You just need to unwrap it like this:

var number1: Double = (first! as NSString).doubleValue
var number2: Double = (second! as NSString).doubleValue

Or you can use this way which is safe:

if let first = previewLable.text, second = lable1.text{
    var number1: Double = (first as NSString).doubleValue
    var number2: Double = (second as NSString).doubleValue
}

And for info about ? and ! read this.

Swift, Convert String To Double Error

2 Answers2