Convert double in Dart

Question

I have the following number in decimal double x = 2.888888888888889; , but I have not been able to obtain 2.9 as a result.How is it done? is there a way to do this? that approaches 1 decimal more like the rules of mathematics? if it is 3.5 that the result is 3.6 ?

`double.round()` In mathematics, if it's 3.5 then it's 4.0 when approximated at least that's what i was taught. Check [round](https://api.flutter.dev/flutter/dart-core/double/round.html) — Frank nike, Mar 17 '22 at 21:21
@Franknike Use round() but it doesn't work for me, must be more exact result. — Nautilus, Mar 17 '22 at 21:26

score 2 · Accepted Answer · answered Mar 17 '22 at 21:29

2

There are at least two ways, check this out:

void main() {

  double number = 2.888888888;
  
  double roundedByString = double.parse(number.toStringAsFixed(1));
  print(roundedByString); // prints 2.9
  
  double roundedByTenthInt = (number * 10).round() / 10;
  print(roundedByTenthInt); // prints 2.9
}

answered Mar 17 '22 at 21:29

tmaihoff

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You are the answer that I was looking for so much, you have saved me, thank you !! – Nautilus Mar 17 '22 at 21:38
Be aware that what this will do is to set `roundedByString` and `roundedByTenthInt` to the `double` value *nearest* to 2.9 (which will be 2.899999999999999911182158029987476766109466552734375). You inherently cannot exactly round most *binary* floating-point numbers to a *decimal* precision. Also see https://stackoverflow.com/a/68980598/ – jamesdlin Mar 17 '22 at 22:08

Convert double in Dart

1 Answers1