Adventures in Machine Learning

Mastering Fraction Manipulation in Python

Fractions are numbers that represent a part of a whole. Fractions consist of two numbers, a numerator and a denominator, separated by a slash (/).

In Python, we can work with fractions using the built-in fractions module.

Creating and Initializing Fractions

In Python, we can create fractions using the Fraction class in the fractions module. To create a fraction, we can use the constructor of the Fraction class.

The constructor takes two arguments, numerator and denominator, separated by a comma. For example, to create a fraction 3/4, we can use the following code:


from fractions import Fraction

frac = Fraction(3, 4)


The constructor also has some additional arguments, like zero, one, and infinity, which represent the corresponding fractions. For example, to create the fraction 0, we can use the following code:


frac = Fraction(0)


Rational Numbers

A rational number is a number that can be expressed as a fraction. In Python, we can work with rational numbers using the Fraction class.

The numerator and denominator of a fraction can be integers or long integers. When we create a fraction, the constructor automatically simplifies it to its lowest terms.

For example, the fraction 6/8 is simplified to 3/4.

Floating-Point and Decimal Numbers

Floating-point numbers are decimal numbers that use a fixed number of digits to represent real numbers. In Python, we can work with floating-point numbers using the built-in float data type.

However, due to the way floating-point numbers are represented in a computer, they can sometimes lead to rounding errors. This can be problematic, especially when working with financial calculations or other precise computations.

Another way to represent decimal numbers in Python is to use the decimal module. The decimal module provides a Decimal class that can represent decimal numbers with arbitrary precision.

The Decimal class uses a fixed number of digits, but it avoids the rounding errors of floating-point numbers. When we create a Decimal object, we can specify the precision and rounding modes.

Working with Strings

In Python, we can convert fractions to strings using various formatting methods. There are two common formats for representing fractions in string form.

The first is to represent the fraction as a decimal number. For example, the fraction 3/4 can be represented as the decimal number 0.75.

The second format represents the fraction as a fractional notation, where the numerator and denominator are separated by a slash (/). To represent a fraction as a decimal number, we can use the str() function or use string formatting.

For example, to convert the fraction 3/4 to a string as a decimal number with two decimals, we can use the following code:


frac = Fraction(3, 4)

str(frac) # ‘3/4’

“{:.2f}”.format(frac) # ‘0.75’


Performing Arithmetic Operations with Fractions

We can perform basic arithmetic operations on fractions using the arithmetic operators. The addition, subtraction, multiplication, and division operators (+, -, *, /) work the same way as they do with other Python data types.

When we add or subtract fractions, we need to have a common denominator.

Converting fractions to other data types

In Python, we can convert fractions to other data types using the built-in int() and float() functions. When we convert a fraction to an integer, we round towards zero.

When we convert a fraction to a floating-point number, we get an approximation of the true value.

The limit_denominator() method

The Fraction class also provides a method called limit_denominator(). This method returns a new fraction that is a close approximation of the original fraction, but with a limited denominator.

The limit_denominator() method can be used to obtain a fraction that is easier to work with or to compare to another fraction.

Comparing fractions

We can compare fractions using the comparison operators <, >, <=, >=, ==, and !=. When we compare fractions, we first compare their numerator and then their denominator.

Applying standard mathematical functions

We can apply standard mathematical functions to fractions using the math module. The math module provides functions like abs(), round(), pow(), and others that work with numbers of any data type, including fractions.


Fractions are an essential concept in mathematics and computer science. In Python, we can work with fractions using the built-in fractions module.

Creating and initializing fractions is straightforward, and there are various formatting methods for working with fraction strings. We can perform arithmetic operations on fractions using the arithmetic operators, convert fractions to other data types, compare fractions, and apply standard mathematical functions to fractions using the math module.

By understanding these concepts, we can work effectively with fractions in Python and solve various mathematical and computational problems.

Editing Fractions

Fractions in Python can be edited using a variety of methods. We can simplify fractions by finding their greatest common divisor (GCD) and dividing the numerator and denominator by it.

We can also invert fractions by swapping their numerator and denominator, and we can change their signs by multiplying the numerator or denominator by -1. Additionally, we can round or modify the fractional precision of fractions to match specific use cases.

Simplifying Fractions

To simplify a fraction in Python, we need to find its greatest common divisor (GCD) and divide both the numerator and denominator of the fraction by it. Python provides us with the built-in gcd function (from the math module) for computing GCD easily.

Here’s an example of how to use the function:


from math import gcd

from fractions import Fraction

frac = Fraction(24, 36)

common_divisor = gcd(frac.numerator, frac.denominator)

simplified_frac = Fraction(frac.numerator // common_divisor, frac.denominator // common_divisor)


Here, we create a fraction using the Fraction constructor, whose numerator and denominator are not co-prime. We then use the gcd function to find the common divisor for both the numerator and denominator.

Finally, we divide both the numerator and denominator by the common divisor to create a new, simplified fraction.

Inverting Fractions

To invert a fraction, we simply swap its numerator and denominator. This could be useful if we want to find the reciprocal of a fraction for a specific use case.

Here’s an example:


frac = Fraction(3, 5)

inverted_frac = Fraction(frac.denominator, frac.numerator)


Here, we create a fraction and then swap its numerator and denominator to create a new fraction with its value inverted.

Making Fractions Proper or Improper

A proper fraction is a fraction whose numerator is less than its denominator. Conversely, an improper fraction is a fraction whose numerator is greater than or equal to its denominator.

To convert a fraction from improper to proper or vice versa, we can use the integer division operator (//) to find the quotient and remainder of the division of the numerator by the denominator. Here’s an example:


frac = Fraction(12, 5)

if frac.numerator >= frac.denominator:

improper_frac = frac

proper_frac = Fraction(frac.numerator // frac.denominator, frac.numerator % frac.denominator, frac.denominator)


proper_frac = frac

improper_frac = Fraction(0, frac.numerator, frac.denominator)


Here, we create a fraction and check whether it is proper or improper.

If it is improper, we use integer division to convert it to a mixed number. If it is already proper, we simply keep it as it is.

Changing Signs

To change the sign of a fraction, we can multiply either the numerator or denominator by -1. Here’s an example:


frac = Fraction(5, -7)

positive_frac = Fraction(abs(frac.numerator), abs(frac.denominator))

negative_frac = Fraction(abs(frac.numerator) * -1, abs(frac.denominator))


Here, we create a fraction with a negative numerator and use the abs() function to get the absolute values of the numerator and denominator.

We then create a new fraction with both the numerator and denominator as positive. We also create a new fraction where only the numerator has been multiplied by -1 to change the sign.

Rounding Fractions

Rounding fractions can be useful when we need to limit the precision of a fraction to a specific number of decimal places. We can use the round() function to round a fraction to a specified number of decimal places.

Here’s an example:


frac = Fraction(4, 7)

rounded_frac = round(float(frac), 2)


Here, we create a fraction and use the float() function to convert it to a floating-point number. We then use the round() function to round it to two decimal places.

Handling Fractions in Real-Life Scenarios

Fractions have many use-cases in real-life scenarios. One common application of fractions is in cooking, where chefs need to measure precise quantities of ingredients.

Fractions are also widely used in the field of construction, where precise measurements of walls, floors, and ceilings are essential. In finance, fractions are used to calculate interest rates, dividends, and stock values.

Comparison with Decimals

While decimals and fractions are both used to represent real numbers, there are some key differences between them. Decimals represent numbers in base-ten notation and have a fixed number of decimal places, whereas fractions can represent any precise value.

Fractions are generally more accurate than decimals as there is no rounding involved.

Comparison with Floating-Point Numbers

Floating-point numbers, like decimals, are a convenient way to represent real numbers in Python. However, floating-point numbers can suffer from rounding errors and are less precise than fractions.

Additionally, floating-point operations are generally slower than operations on integer and fractional numbers because they need to use specialized hardware.

Performance Considerations

When working with fractions in Python, it’s important to consider performance when dealing with larger fractions. Python’s built-in fractions module can be slow for some operations that require high-precision calculations.

This is where the quicktions module comes into play. The quicktions module provides an alternative implementation of fractions that is designed for quick computation and provides a range of advanced features.

While the syntax is different from that of the built-in fractions module, the quicktions module is an excellent choice when dealing with larger and more complex fractions.


Python provides a variety of methods for editing and working with fractions that make them powerful tools for a wide range of real-world applications. From simplifying and inverting fractions to rounding and converting floating-point numbers, there are many ways to modify fractions to match specific use cases.

By understanding these methods, we can develop more robust and accurate code that takes full advantage of the power of fraction data types. In conclusion, fractions play a crucial role in mathematics and are used in many real-life scenarios such as cooking, construction, and finance.

In Python, fractions can be created, edited, and manipulated in various ways, including simplifying, inverting, and rounding. Comparing and handling fractions with decimals and floating-point numbers pose certain challenges and require precision.

When working with larger fractions, the quicktions module provides a faster alternative. By understanding the methods of editing and handling fractions in Python, developers can create more precise and accurate code that takes full advantage of the power of fraction data types.

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