PHP Fraction

PHP fraction library with fraction simplification and float to fraction conversion.

Installation

Install via Composer:

composer require hughgrigg/php-fraction

Usage

Import the fraction class:

use Fraction\Fraction;

Creating fractions

Create fractions with the numerator and denominator:

$half = new Fraction(1, 2);
$third = new Fraction(1, 3);
$threeFifths = new Fraction(3, 5);
$oneAndAQuarter = new Fraction(5, 4);

Simplifying fractions

Simplify fractions with the simplified() method:

$fiveTenths = new Fraction(5, 10);
$simplified = $fiveTenths->simplified();
// = new Fraction(1, 2)

The fraction object is immutable, so the original instance is unchanged.

Converting floats to fractions

Get a fraction from a float with the FloatConversion class:

use Fraction\FloatConversion;

$half = (new FloatConversion(0.5))->fraction();
// = new Fraction(1, 2);

Float conversion precision

You might not want arbitrary precision when converting a float to a fraction. For example, you might prefer that 0.249 is converted to 1/4, and not 249/1000.

You can do this by setting the precision on the float conversion. This sets the tolerance to use when finding the closest fraction for the float:

$almostAQuarter = (new FloatConversion(0.249))->withPrecision(0.1)->fraction();
// = new Fraction(1, 4);

$almostAQuarter->withPrecision(0.01)->fraction();
// = new Fraction(24, 100);

$almostAQuarter->withPrecision(0.001)->fraction();
// = new Fraction(249, 1000);

Again, the FloatConversion object is immutable, so the original instance is unchanged when doing this.

The default precision is 0.001 (one thousandth).

Converting fractions to floats

You can get the float equivalent of a fraction with the asFloat() method:

$threeFifths = new Fraction(3, 5);
$threeFifths->asFloat();
// = 0.6

$oneThird = new Fraction(1, 3);
$oneThird->asFloat();
// = 0.33333333333333

Converting fractions to percentages

You can get the percentage equivalent of a fraction with the float() method:

$threeFifths = new Fraction(3, 5);
$threeFifths->asPercentage();
// = 60

$oneThird = new Fraction(1, 3);
$oneThird->asPercentage();
// = 33.333333333333

Fraction operations

You can apply various arithmetic operations to fractions. Note that the results are not simplified automatically, so you will need to use the simplified() method at the end of your calculations to get the simplified form of the result.

Addition

$half = new Fraction(1, 2);
$third = new Fraction(1, 3);
$sum = $half->add($third);
// = new Fraction(5, 6)

$tenth = new Fraction(1, 10);
$fifth = new Fraction(1, 5);
$sum = $tenth->add($fifth);
// = new Fraction(15,50)
$sum->simplified();
// = new Fraction(3, 10)

Subtraction

$half = new Fraction(1, 2);
$third = new Fraction(1, 3);
$difference = $half->subtract($third);
// = new Fraction(1,6)

$fifth = new Fraction(1, 5);
$tenth = new Fraction(1, 10);
$difference = $fifth->subtract($tenth)
// = new Fraction(5, 50)
$difference->simplified();
// = new Fraction(1, 10)

Multiplication

$half = new Fraction(1, 2);
$third = new Fraction(1, 3);
$product = $half->multiplyBy($third);
// = new Fraction(1,6)

$twoFifths = new Fraction(2, 5);
$tenth = new Fraction(1, 10);
$product = $twoFifths->multiplyBy($tenth)
// = new Fraction(2, 50)
$product->simplified();
// = new Fraction(1, 25)

Division

$half = new Fraction(1, 2);
$third = new Fraction(1, 3);
$quotient = $half->divideBy($third);
// = new Fraction(3,2)

$twoFifths = new Fraction(2, 5);
$tenth = new Fraction(1, 10);
$product = $twoFifths->multiply($tenth)
// = new Fraction(2, 50)
$difference->simplified();
// = new Fraction(1, 25)

Comparison

You can check strict equality of fractions with the equals() method:

$half = new Fraction(1, 2);
$threeSixths = new Fraction(3, 6);
$half->equals($threeSixths);
// = true

$twoSixths = new Fraction(2, 6);
$half->equals($twoSixths);
// = false

If you want to check with a loose precision, you can use the equalsWithin() method, which takes the other fraction and the precision to compare in:

$half = new Fraction(1, 2);
$threeEights = new Fraction(3, 8);
$half->equalsWithin($threeEights, 0.25);
// = true

Fraction string conversion

The __toString() method on the Fraction class prints out the fraction using a slash for the divider:

$fraction = new Fraction(1, 3);
$useInString = "The fraction is {$fraction}";
// = 'The fraction is 1/3'

$fraction = new Fraction(8, 5);
$useInString = "The fraction is {$fraction}";
// = 'The fraction is 1 3/5'

String conversion with unicode fractions

Unicode provides some entities for representing fractions directly as a single character. You can use these in string conversion with the unicodeChars() method:

$fraction = new Fraction(1, 3);
$useInString = "The fraction is {$fraction->unicodeChars()}";
// = 'The fraction is ⅓'

$fraction = new Fraction(8, 5);
$useInString = "The fraction is {$fraction->unicodeChars()}";
// = 'The fraction is 1 ⅗'

There are not many of these fraction characters in Unicode. However, you can go further and build any fraction you want using Unicode subscripts and superscripts. These allow any arbitrary fraction, but are less likely to render as expected in different situations.

To convert to a string with Unicode superscripts and subscripts, use the unicodeScripts() method:

$fraction = new Fraction(1, 6);
$useInString = "The fraction is {$fraction->unicodeScripts()}";
// = 'The fraction is ¹⁄₆'

$fraction = new Fraction(10, 6);
$useInString = "The fraction is {$fraction->unicodeChars()}";
// = 'The fraction is 1 ⁴⁄₆'