Unable to multiply two string values in swift - json

Question

I am getting float value in string format from JSON like below
JSON:
{
"result": {
"conversion_factor": {
"conv_factor": "0.820000"
}
"search_result": [
{
"service_details": [
{
"standard_rate_in_usd": "10.00",
now i need to multiply conv_factor * standard_rate_in_usd
code: with this code only first value coming correct remaining showing wrong why?
let indexData = searchResult?.result?.search_result?[indexPath.row]
if let servDetls = indexData?.service_details{
for oneSerdet in servDetls{
var stringPrice: String?
if var priceVal = Float(oneSerdet.standard_rate_in_usd!), var convVal = Float((searchResult?.result?.conversion_factor?.conv_factor)!) {
stringPrice = String(priceVal * convVal)
}
else{
stringPrice = ""
}
cell.priceLbl.text = "£ \(stringPrice ?? "") \(currData)"
}
}

Answer 1

You need to convert to floats:
let convResult = Float(oneSerdet.standard_rate_in_usd) *
Float(searchResult?.result?.conversion_factor?.conv_factor)

Answer 2

Try this, hope this will resolves your issue
if let conv_factor = oneSerdet.conv_factor,
let factor = Double(conv_factor),
let standard_rate_in_usd = oneSerdet.standard_rate_in_usd,
let usd = Double(standard_rate_in_usd) {
print(factor*usd)
cell.priceLbl.text = "\(factor*usd)"
}else{
cell.priceLbl.text = ""
print("Unreachable")
}

Answer 3

You have multiple problems:
Your construct searchResult?.result?.conversion_factor?.conv_factor evaluates to an Optional String: String?.
You can't multiply strings. Strings are not numeric. You need to convert your string to a Double. But the Double initializer that takes a string also returns an Optional (since "Apple", for example, can't be converted to a Double.
Here is some sample code that will take 2 Optional Strings, try to convert them to Doubles, and multiples them.
let xString: String? = "123.456"
let yString: String? = "2.0"
let x = xString.map { Double($0) ?? 0 } ?? 0.0
let y = yString.map { Double($0) ?? 0 } ?? 0.0
let result: Double = x * y
print(result)
That outputs
246.912