1. pow, round 를 이용하는 방법 (math 라이브러리 필요)
2. double.parse, toStringAsFixed 를 이용하는 방법
3. intl 패키지의 NumberFormat 을 이용하는 방법
| import 'dart:math' as math; | |
| import 'package:flutter_test/flutter_test.dart'; | |
| class TestSet { | |
| final num number; | |
| final int pre; | |
| final double expected; | |
| TestSet(this.number, this.pre, this.expected); | |
| } | |
| void main() { | |
| final tester = [ | |
| TestSet(12.3123, 2, 12.31), | |
| TestSet(31.47, 1, 31.5), | |
| TestSet(5927.9978, 2, 5928.0), | |
| TestSet(5927.9978, 3, 5927.998), | |
| TestSet(5927.8978, 2, 5927.9), | |
| TestSet(12345.126, 2, 12345.13), | |
| TestSet(0.12345, 4, 0.1235), | |
| ]; | |
| group('round num 2 tester', () { | |
| var start = DateTime.now(); | |
| for (var element in tester) { | |
| test('test $element', () { | |
| num number = element.number; | |
| int pre = element.pre; | |
| num aa = number.rightRoundNum(pre); | |
| // expect(number.rightRoundNum(pre), aa); | |
| expect(element.expected, aa); | |
| print("input : $number, $number.roundNum($pre) : $aa"); | |
| }); | |
| } | |
| var diff = DateTime.now().difference(start); | |
| print(diff); | |
| start = DateTime.now(); | |
| for (var element in tester) { | |
| test('test $element', () { | |
| num number = element.number; | |
| int pre = element.pre; | |
| num aa = number.roundNum(pre); | |
| // expect(number.rightRoundNum(pre), aa); | |
| expect(element.expected, aa); | |
| print("input : $number, $number.roundNum($pre) : $aa"); | |
| }); | |
| } | |
| diff = DateTime.now().difference(start); | |
| print(diff); | |
| }); | |
| } | |
| extension RoundWithPrecision on num { | |
| num roundNum(int precision) { | |
| final mod = math.pow(10, precision); | |
| return (this * mod).round() / mod; | |
| } | |
| num rightRoundNum(int precision) { | |
| return double.parse(toStringAsFixed(precision)); | |
| } | |
| /// NumberFormat 사용하는 방법 | |
| // num formatRoundNum(int precision) { | |
| /// intl 있어야 함 | |
| // } | |
| } |