How to convert Exponential Value to Decimal Value - swift

Question

let balance = "2.477854178281608e-06"
// I have to convert this exponential value in Decimal
/* Already tried the below-mentioned solution, but not working */
let numberFormatter = NumberFormatter()
numberFormatter.numberStyle = .decimal
let finalNumber = numberFormatter.number(from: balance)
print(finalNumber!)
Value is printing "2.477854178281608e-06\n"
Any help will be appreciated.

Answer 1

let balance = "2.477854178281608e-06"
// I have to convert this exponential value in Decimal
This is not an exponential value. This is a string that represents a number using exponential format. You seem to want a string representing the same number in a different format. The important thing here is that neither string is "the value." The value is the same regardless of representation (or approximately the same if the representation is limited).
So first you need the value represented by the string. To do that, convert it to a Double.
let value = Double(balance)!
Now, you say you want to convert that to a string in decimal format (I assume you mean 0.000...). So you need a formatter:
let numberFormatter = NumberFormatter()
numberFormatter.numberStyle = .decimal
numberFormatter.maximumFractionDigits = 20
let string = numberFormatter.string(for: value)!
print(string) // 0.00000247785417828161
You'll note that this value is slightly different than the previous value. That's because there are rounding errors when dealing with values this small.
If all of these base-10 digits are important, you can work with the Decimal type rather than Double. This avoids decimal/binary rounding, but is less convenient and slower for some kinds of math. If this is a type of currency that is expressed in base-10 units (which is basically all of them), you always want to work with Decimal and never with Double.
let balance = "2.477854178281608e-06"
let value = Decimal(string: balance)!
let numberFormatter = NumberFormatter()
numberFormatter.numberStyle = .decimal
numberFormatter.maximumFractionDigits = 21
let string = numberFormatter.string(for: value)!
print(string) // 0.000002477854178281608