fraction 2.0.1

A package that helps you dealing with mathematical fractions. Work with fractions, mixed fractions and types conversions.

example/README.md

You can create an instance of Fraction using one of its constructors.

• Basic: it just requires the numerator and/or the denominator.

  final frac = Fraction(3, 5); // 3/5
  final frac = Fraction(3, 1); // 3
  

• String: pass the fraction as a string but it has to be well-formed otherwise an exception is thrown.

  final frac1 = Fraction.fromString("2/4"); // 2/4
  final frac2 = Fraction.fromString("-2/4"); // -2/4
  final frac3 = Fraction.fromString("2/-4"); // Error
  final frac4 = Fraction.fromString("-2"); // -2/1
  

• double: represents a double as a fraction. Note that irrational numbers cannot be converted into a fraction by definition; the constructor has the precision parameter which decides how precise the representation has to be.

  final frac1 = Fraction.fromDouble(1.5); // 3/2
  final frac2 = Fraction.fromString(-8.5); // -17/2
  final frac3 = Fraction.fromString(math.pi); // 208341/66317
  final frac4 = Fraction.fromString(math.pi, 1.0E-4); // 333/106
  

  The constant pi cannot be represented as a fraction because it's an irrational number. The constructor considers only precison decimal digits to create a fraction. With rational numbers instead you don't have problems.

Thanks to extension methods you can also create a Fraction object "on the fly" by calling the toFraction() method on a number or a string.

final f1 = 5.toFraction(); // 5/1
final f2 = 1.5.toFraction(); // 3/2
final f3 = "6/5".toFraction(); // 6/5

You can easily sum, subtract, multiply and divide fractions thanks to the operators:

final f1 = Fraction(5, 7);
final f2 = Fraction(1, 5);

final sum = f1 + f2; // -> 5/7 + 1/5
final sub = f1 - f2; // -> 5/7 - 1/5
final mul = f1 * f2; // -> 5/7 * 1/5
final div = f1 / f2; // -> 5/7 / 1/5

The method reduce() reduces the fraction to the lowest terms.

final fraction = Fraction.fromString("12/20");  // 12/20
final reduced = fraction.reduce();              // 3/5

Two fractions are equal if their "cross product" is equal. For example 1/2 and 3/6 are said to be equivalent because 1*6 = 3*2 (and in fact 3/6 is the same as 1/2). The API is very wide:

final fraction1 = Fraction(10, 2).toDouble();  // 5.0
final fraction2 = Fraction(10, 2).inverse();   // 2/10
final fraction3 = Fraction(1, 15).isWhole;     // false

final sum = fraction1 + fraction3; // 76/15

Working with mixed fractions

A mixed fraction is made up of a whole part and a proper fraction (a fraction in which numerator <= denominator). It's easy to build a MixedFraction object:

final f1 = MixedFraction(3, 4, 7);
final f2 = MixedFraction.fromDouble(1.5);
final f3 = MixedFraction.fromString("1 1/2");

There is also the possibility to initialize a MixedFraction using extension methods:

final f1 = "1 1/2".toMixedFraction();

If you try to create an instance in which the numerator is greater than the denominator, a MixedFractionException is thrown.