Variables and Data Types in Python

#python

Introduction to variables in python: An in-dept walkthrough

Introduction to Variables in python

Variables in Python are names (mostly referred to as containers) that are used to store data values. You can think of them as labeled boxes that hold information so you can use or change it later.

Python is dynamically typed: (so a datatype declaration is not enforced beforehand)
A variable points to a value in memory

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Variables and Data Types in Python

A full article is dedicated to explaining data types in detail, but here’s a brief overview of the basic data types you can assign to variables in Python:

String – A sequence of characters, enclosed in quotes.
Example: "Hello world"
Integer – Whole numbers without decimal points.
Example: 1, 2, 3, 4
Float – Numbers with decimal points (floating-point numbers).
Example: 3.2, 0.4, 4.23
Boolean – Represents either True or False.
Example: True, False
List – An ordered, changeable collection of items.
Example: [2, 4, 5]
Tuple – An ordered, unchangeable collection of items.
Example: (2, 4, 5)
Dictionary – A collection of key-value pairs.
Example: {"name": "Bright", "age": 26}
Set – An unordered collection of unique items.
Example: {1, 2, 3, 3} → becomes {1, 2, 3}
NoneType – Represents the absence of a value.
Example: None

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# String greeting = "Hello world" # Integer age = 25 # Float pi = 3.14 # Boolean is_active = True # List numbers = [2, 4, 5] # Tuple coordinates = (10, 20) # Dictionary person = {"name": "Bright", "age": 26} # Set unique_values = {1, 2, 3, 3} # duplicate 3 will be removed # NoneType result = None # Display types print("greeting:", greeting, "| Type:", type(greeting)) print("age:", age, "| Type:", type(age)) print("pi:", pi, "| Type:", type(pi)) print("is_active:", is_active, "| Type:", type(is_active)) print("numbers:", numbers, "| Type:", type(numbers)) print("coordinates:", coordinates, "| Type:", type(coordinates)) print("person:", person, "| Type:", type(person)) print("unique_values:", unique_values, "| Type:", type(unique_values)) print("result:", result, "| Type:", type(result))

Output:

Variable Naming Rules

There are a few important rules to follow when choosing a variable name in Python:

Variable names can include letters, numbers, and underscores.
A variable name cannot start with a number.
Variable names are case-sensitive (e.g., name, Name, and NAME are all different).
You cannot use reserved keywords (like if, class, or def) as variable names.

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Case Sensitivity

Python is a case-sensitive language, which means that “name” is not the same as “Name” if you pay close attention, there is a slight difference between both because the first is all lowercase while the second is capitalized

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Output:

Reassigning Variables

In Python, variables are dynamically typed, meaning you don't need to declare their type ahead of time. More specifically, you can change the type of a variable at any point in your code.

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Output:

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