CODEWITHSUNDEEP
iosarraysstringswiftdouble
somepers
somepers

Reputation: 529

Swift - Convert values in array to doubles or floats

I have an array with values which are strings (but all the strings are values like 1.0, 2.0, etc). I'm trying to convert those strings into doubles or floats so I can add them all together. How do I do this in swift?

Upvotes: 5

Views: 11806

Answers (4)

Raksha.
Raksha.

Reputation: 519

Swift 5.1

extension Collection where Iterator.Element == String {
    var convertToDouble: [Double] {
        return compactMap{ Double($0) }
    }
    var convertToFloat: [Float] {
        return compactMap{ Float($0) }
    }
}

Example How to Use

let String_Array = ["1.5","2.3","3.7","4.5"]       // ["1.5", "2.3", "3.7", "4.5"]
let Double_Array = String_Array.convertToDouble    // [1.5, 2.3, 3.7, 4.5]
let Float_Array = String_Array.convertToFloat.     // [1.5, 2.3, 3.7, 4.5]

OR You can do this

let numArray = ["1.0","2.0","3.0"]
let stringFromArray = numberArray[0]
let floatFromString = Float(stringFromArray)
let doubleFromString = Double(stringFromArray)

Upvotes: 3

Leo Dabus
Leo Dabus

Reputation: 236360

update: Xcode 8.3.2 • Swift 3.1

extension Collection where Iterator.Element == String {
    var doubleArray: [Double] {
        return flatMap{ Double($0) }
    }
    var floatArray: [Float] {
        return flatMap{ Float($0) }
    }
}

usage:

let strNumbersArray = ["1.5","2.3","3.7","4.5"]   // ["1.5", "2.3", "3.7", "4.5"]
let doublesArray = strNumbersArray.doubleArray    // [1.5, 2.3, 3.7, 4.5]
let floatsArray = strNumbersArray.floatArray      // [1.5, 2.3, 3.7, 4.5]
let total = doublesArray.reduce(0, +)     // 12
let average = total / Double(doublesArray.count)  // 3

If you have an Array of Any? where you need to convert all strings from Optional Any to Double:

extension Collection where Iterator.Element == Any? {
    var doubleArrayFromStrings: [Double] {
        return flatMap{ Double($0 as? String ?? "") }
    }
    var floatArrayFromStrings: [Float] {
        return flatMap{ Float($0 as? String ?? "") }
    }
}

usage:

let strNumbersArray:[Any?] = ["1.5","2.3","3.7","4.5", nil]   // [{Some "1.5"}, {Some "2.3"}, {Some "3.7"}, {Some "4.5"}, nil]
let doublesArray = strNumbersArray.doubleArrayFromStrings    // [1.5, 2.3, 3.7, 4.5]
let floatsArray = strNumbersArray.floatArrayFromStrings      // [1.5, 2.3, 3.7, 4.5]
let total = doublesArray.reduce(0, +)     // 12
let average = total / Double(doublesArray.count)  // 3

Upvotes: 6

seto nugroho
seto nugroho

Reputation: 1379

if you are sure that all of your array is string, you can directly cast your string into float or double.

let numberArray:Array = ["1.0","2.0","3.0"]
let stringFromArray = numberArray[0]
let floatFromString = Float(stringFromArray)
let doubleFromString = Double(stringFromArray)

Upvotes: 1

BallpointBen
BallpointBen

Reputation: 13750

let x = ["1.0", "1.5", "2.0"]
print(x.map {Double($0)!})

Upvotes: 7

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