Python Constants - Explained

Python Constants are used to indicate that a value assigned to them should not be changed. This makes them ideal for use in mathematical equations or as part of a program's interface. In this post, we'll take a look at how to create constants, and we'll also provide some examples of where they can be useful.

Table of Contents

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Python Syntax - Everything you need...
Python Syntax - Everything you need to know!

What are Constants in Python?

Python offers several built-in constants, such as True, False, and None. Python also allows users to create their custom constants using the keyword None.

Constants are stored in memory, and they are accessed using their respective names. Constants can be of any data type, including integers, floats, strings, and tuples. Constants are typically used to represent unchanging values in a Python program, such as the value of pi or the number of days in a week. When creating constants, it is important to choose names that accurately describe their purpose.

Since constants do not officially exist, their value can be changed during program execution. Constants are used to indicate a value that should not be touched if working together with other programmers.

How do you create a Constant in Python?

Constants are created by using capitalized letters separated by underscores (_). A simple constant with a string value looks like this:

CAPITAL_OF_GERMANY = "Berlin"
Code language: Python (python)

Python Constants can be changed

This means that you can change their value during runtime. Let's assume we want to change the string value of the CAPITAL_OF_GERMANY constant from "Berlin" to "Munich" during runtime:

# A constant in Python CAPITAL_OF_GERMANY = "Berlin" print(CAPITAL_OF_GERMANY) # Changing constants in Python is possible CAPITAL_OF_GERMANY = "Munich" print(CAPITAL_OF_GERMANY)
Code language: Python (python)

Output:

Python Constants

Using constants is merely an indicator for other developers working on your code that certain values should not be changed.

Python Constants Naming Conventions

Constants should always be named in all capital letters separated by underscores (_). Here are some examples:

MY_HOME_ADDRESS = "Sunnylane 23" MY_BIRTHYEAR = 1982 BEER_TASTES_GOOD = True
Code language: Python (python)

Constants in Python Examples

Some more examples of all the different use-cases where constants can be used:

Lists

OUR_LIST = ["Apples", "Bananas", "Mangoes"]
Code language: Python (python)

Tuples

OUR_TUPLE = ("Apples", "Bananas", "Mangoes")
Code language: Python (python)

Dictionaries

OUR_DICT = {"Fruit": "Mango", "Vegetable": "Carrot"}
Code language: Python (python)

Summary

To summarize, constants are mainly used to indicate to other developers that certain variables shouldn't be changed.

  • Constants are written with capitalized letters separated by underscores (_).
  • Constants can be changed.
  • Constants can be booleans, strings, integers, lists, tuples, and dictionaries, among others.
  • We can create as many constants as we like.

🐍 Learn Python Programming
🔨 Python Basics
👉 Python Syntax
👉 Python Variables
👉 Python print()
👉 Python input()
👉 Python Constants
⚙️ Python Specifics
👉 Python List Replace - Simplified
👉 Create a GUI in Python
👉 Find out the Length of a String in Python
👉 Enum in Python
🏋️ Python Exercises
👉 Python Exercise Collection

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