If you’re like me, you probably think that decimals are just numbers with a dot in them. But did you know that there’s actually an entire Python library dedicated to working with these little guys?
That’s right, the decimal module is here to save us from the headaches of floating point math (which we won’t even get into because it’s like trying to explain quantum physics to a cat). Instead, let’s focus on some of the coolest class methods that this library has to offer.
First up: `Decimal.__new__()` the constructor method for creating new decimal objects. This is where you can specify your initial value as either a string or an integer (which will be converted to a string). For example, let’s say we want to create a decimal object with the value 3.14:
# Import the Decimal class from the decimal module
from decimal import Decimal
# Create a new decimal object with the value 3.14 using the Decimal constructor method
my_decimal = Decimal('3.14')
# Print the decimal object
print(my_decimal) # Output: Decimal('3.14')
# The Decimal constructor method allows us to specify the initial value of the decimal object as either a string or an integer, which will be converted to a string.
# In this case, we are creating a decimal object with the value 3.14 by passing in a string '3.14' as the argument.
# This ensures that the decimal object accurately represents the value we want, without any potential rounding errors that may occur when using floating point numbers.
Or, if you prefer to use integers instead of strings (because who has time for typing all those digits?), you can do this:
# Importing the Decimal module from the decimal library
from decimal import Decimal
# Defining a variable "my_integer" and assigning it an integer value of 256
my_integer = 256
# Converting the integer value to a decimal value using the Decimal constructor and assigning it to the variable "my_decimal"
my_decimal = Decimal(my_integer)
# Printing the decimal value of "my_decimal" to the console
print(my_decimal) # Output: Decimal('256')
Next up, we have `Decimal.__add__()`, which allows us to add two decimal objects together. This is useful for all sorts of calculations from adding up your grocery list to calculating the total cost of a product on an e-commerce site:
# Import the Decimal module from the decimal library
from decimal import Decimal
# Create a decimal object with a value of 3.14 and assign it to the variable my_decimal1
my_decimal1 = Decimal('3.14')
# Create another decimal object with a value of 5.98 and assign it to the variable my_decimal2
my_decimal2 = Decimal('5.98')
# Add the two decimal objects together using the __add__() method and assign the result to the variable result
result = my_decimal1.__add__(my_decimal2)
# Print the result of the addition, which will be a decimal object with a value of 9.12
print(result) # Output: Decimal('9.12')
We also have `Decimal.__mul__()`, which allows us to multiply two decimal objects together (because who doesn’t love a good multiplication problem?):
# Import the Decimal module from the decimal library
from decimal import Decimal
# Create a decimal object with the value of 3.14 and assign it to the variable my_decimal1
my_decimal1 = Decimal('3.14')
# Create another decimal object with the value of 5.98 and assign it to the variable my_decimal2
my_decimal2 = Decimal('5.98')
# Multiply the two decimal objects together and assign the result to the variable result
result = my_decimal1 * my_decimal2
# Print the result of the multiplication, which will be a decimal object with the value of 19.6704
print(result) # Output: Decimal('19.6704')
And if you’re feeling really fancy, we can even use the `Decimal.__pow__()` method to raise a decimal object to an exponent (because who doesn’t love some good old-fashioned math puns?):
# Import the Decimal module from the decimal library
from decimal import Decimal
# Create a decimal object with a value of 3.14 and assign it to the variable my_decimal1
my_decimal1 = Decimal('3.14')
# Use the Decimal.__pow__() method to raise my_decimal1 to the power of 2 and assign the result to the variable result
result = my_decimal1.__pow__(2)
# Print the result of the calculation
print(result) # Output: Decimal('9.859609')
# The script creates a decimal object and uses the Decimal.__pow__() method to perform a calculation and print the result.
We also have `Decimal.__round__()`, which allows us to round a decimal object to the nearest integer (because who doesn’t love some good old-fashioned math puns?):
# Import the Decimal module from the decimal library
from decimal import Decimal
# Create a decimal object with the value of 3.14
my_decimal = Decimal('3.14')
# Use the __round__() method to round the decimal object to the nearest integer
result = my_decimal.__round__()
# Print the result, which should be 3 since we rounded to the nearest integer
print(result) # Output: 3
# Note: The purpose of this script is to demonstrate how to use the __round__() method to round a decimal object to the nearest integer.
And if you’re feeling really fancy, we can even use `Decimal.__quantize__()`, which allows us to round a decimal object to a specific number of decimal places (because who doesn’t love some good old-fashioned math puns?):
# Import the Decimal module from the decimal library
from decimal import Decimal
# Create a decimal object with a value of 3.14
my_decimal = Decimal('3.14')
# Use the __quantize__() method to round the decimal object to 2 decimal places
result = my_decimal.__quantize__(Decimal('0.01'))
# Print the result
print(result) # Output: Decimal('3.14')
# The purpose of this script is to demonstrate how to use the __quantize__() method to round a decimal object to a specific number of decimal places.
Whether you’re working on a math problem or just trying to avoid floating point headaches, this library is here to save us from the madness.