How to Use Variables in Python

Python is a powerful programming language that is widely used for various applications like web development, data analysis, artificial intelligence, and more. One of the fundamental concepts in Python is variables, which are used to store and manipulate data. In this article, we will explore how to use variables in Python, from declaring and initializing them to performing operations and printing their values.

Table of Contents

What are Variables in Python?

A variable is a container that holds a value, which can be of different data types like integers, floating-point numbers, strings, lists, tuples, dictionaries, and more. In Python, variables are dynamically typed, which means that you don’t have to declare the data type explicitly. Instead, the interpreter infers the type based on the assigned value.

For example, you can declare a variable named "age" and assign it an integer value of 25 as follows:

age = 25

This creates a variable named "age" and assigns it the value 25. You can also declare multiple variables in a single line, separated by commas:

name, age, height = "John", 25, 1.75

This creates three variables named "name", "age", and "height" and assigns them the corresponding values of "John", 25, and 1.75. Note that you can assign different data types to different variables in the same line.

Data Types in Python

As mentioned earlier, Python supports different data types, which determine the kind of values that can be stored in a variable. Here are some of the common data types in Python:

  • Integers: Whole numbers without decimals, e.g., 10, -5, 1000
  • Floating-point numbers: Numbers with decimals, e.g., 3.14, 2.5, -0.1
  • Strings: Sequence of characters enclosed in quotes, e.g., "Hello", ‘World’, "123"
  • Booleans: True or False values, used for logical operations, e.g., True, False
  • Lists: Ordered collection of values separated by commas and enclosed in brackets, e.g., [1, 2, 3], ["apple", "banana", "orange"]
  • Tuples: Immutable ordered collection of values separated by commas and enclosed in parentheses, e.g., (1, 2, 3), ("apple", "banana", "orange")
  • Dictionaries: Unordered collection of key-value pairs separated by commas and enclosed in curly braces, e.g., {"name": "John", "age": 25, "height": 1.75}

Each data type has its own set of operations and methods that can be applied to it. For example, you can add two integers using the "+" operator or concatenate two strings using the "+" operator. We will discuss more about these operations in the next sections.

Basic Operations on Variables

Once you have declared and initialized a variable, you can perform various operations on it. Here are some of the basic operations:

Arithmetic Operations

Python supports basic arithmetic operations like addition, subtraction, multiplication, and division. These operations can be applied to numeric data types like integers and floating-point numbers.

a = 10
b = 5

print(a + b) # Output: 15
print(a - b) # Output: 5
print(a * b) # Output: 50
print(a / b) # Output: 2.0

In the above example, we have declared two variables "a" and "b" and performed the four basic arithmetic operations on them using the "+" "-" "*" and "/" operators.

String Operations

Strings can be concatenated using the "+" operator or repeated using the "*" operator.

first_name = "John"
last_name = "Doe"

full_name = first_name + " " + last_name
print(full_name) # Output: John Doe

print(first_name * 3) # Output: JohnJohnJohn

In the above example, we have declared two variables "first_name" and "last_name" and concatenated them to form a full name variable. We have also repeated the first name three times using the "*" operator.

Comparison Operations

Python supports comparison operations like equal to, not equal to, greater than, less than, greater than or equal to, and less than or equal to. These operations return a boolean value of True or False.

a = 10
b = 5

print(a == b) # Output: False
print(a != b) # Output: True
print(a > b) # Output: True
print(a < b) # Output: False
print(a >= b) # Output: True

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