快速从数组中提取值

Question

I'm getting values of string in my response to whom i'm storing in an array. Its is storing properly.Now i want to get that values out of my array because later i have to add that in an another string to get their sum. My array looks like this, [0.5,0.5,0.5]. I have to extract all the 0.5 values and add them. I have tried a code it extract the values but in result it shows 0 value. My code is this,

let itemprice = UserDefaults.standard.string(forKey: "itemPrice")
print(itemprice)
let defaults = UserDefaults.standard
let array = defaults.array(forKey: "addonPrice") as? [Int] ?? [Int]() 
print(array)
let resultant = array.reduce(0, +)
print(resultant)
let result = itemprice! + String(resultant)
print(result)

i'm trying to add the arrays value to another value with the name itemprice. How can i get out all the values from my array and add them. The values in the array varies different time.

Answer 1

You are getting 0 as a result of let resultant = array.reduce(0, +) because in

let array = defaults.array(forKey: "addonPrice") as? [Int] ?? [Int]() 

either the value stored in the defaults is an empty array, or the cast as? [Int] as? [Int] fails.

Considering you claim that the array is supposed to hold values [0.5,0.5,0.5] I assume that it is the latter case. [0.5,0.5,0.5] is an array of Double values, not Int values.

Try to fix it this way:

let array = defaults.array(forKey: "addonPrice") as? [Double] ?? [Double]() 

UPDATE

From comments it seems that you are using strings everywhere, so then:

let itemprice = UserDefaults.standard.string(forKey: "itemPrice")
print(itemprice)
let defaults = UserDefaults.standard
// take it as an array of strings
let array = defaults.array(forKey: "addonPrice") as? [String] ?? [String]()
print(array)
// convert strings to Double
let resultant = array.map { Double($0)! }.reduce(0, +)
print(resultant)
let result = Double(itemprice!)! + resultant 
print(result)

Although I would strongly recommend you to work with Double from the beginning (both to store it and use it).