Basic Concepts – Operators and More

Getting Started with Python Syntax and Basic Constructs

Now that you’ve got Python installed and ran your first program, let’s dive into some fundamental concepts that form the backbone of every Python program. In this post, we’ll cover Python’s syntax, operators, and input/output operations, laying the foundation for writing functional code.

1. Basic Syntax and Structure

Python’s syntax is designed to be clean and easy to read, but there are a few essential rules you need to know before diving into more complex coding.

Indentation

Unlike many other programming languages, Python uses indentation to define code blocks, not braces ({}) or keywords. This makes your code visually cleaner but also means you must be consistent with your spacing.

Code Example: Using Indentation

# Correct indentation  
if True:  
    print("This is properly indented!")  

# Incorrect indentation (will cause an error)  
if True:  
print("This is not properly indented!") 

Comments

Comments are used to make your code more readable and to document what it does. Python uses the # symbol for single-line comments.

# This is a single-line comment  
print("Python ignores comments when running the code.")  

For multi-line comments, use triple quotes:

"""  
This is a  
multi-line comment.  
"""  

Keywords and Identifiers

Keywords: Reserved words in Python, like if, else, for, and def. You cannot use them as variable names.

Identifiers: Names used for variables, functions, or classes. They must start with a letter or an underscore (_) and can’t include special characters.

2. Operators in Python

Operators are symbols used to perform operations on variables and values. Python offers a wide variety of operators.

Arithmetic Operators

Used for basic mathematical operations:

a = 10  
b = 3  

print(a + b)  # Addition  
print(a - b)  # Subtraction  
print(a * b)  # Multiplication  
print(a / b)  # Division  
print(a % b)  # Modulus  
print(a ** b)  # Exponentiation  
print(a // b)  # Floor division 

Comparison Operators

Compare two values and return a Boolean (True or False):

print(a > b)   # Greater than  
print(a < b)   # Less than  
print(a == b)  # Equal to  
print(a != b)  # Not equal to  
print(a >= b)  # Greater than or equal to  
print(a <= b)  # Less than or equal to  

Logical Operators

Combine conditional statements:

x = True  
y = False  

print(x and y)  # Logical AND  
print(x or y)   # Logical OR  
print(not x)    # Logical NOT  

3. Input and Output

Taking Input

Python’s input() function allows you to interact with users by receiving input during program execution.

Code Example: Simple Input

name = input("What is your name? ")  
print(f"Hello, {name}!")  

Displaying Output

The print() function is used to display information. You can also use f-strings for formatted output:

age = 25  
print(f"I am {age} years old.")

4. Mini Project: Basic Calculator

Let’s put everything together to create a simple calculator program that takes user input, performs basic operations, and displays the result.

Code Example: Basic Calculator

# Simple calculator  
num1 = float(input("Enter the first number: "))  
num2 = float(input("Enter the second number: "))  

print("Select operation:")  
print("1. Addition")  
print("2. Subtraction")  
print("3. Multiplication")  
print("4. Division")  

choice = input("Enter your choice (1/2/3/4): ")  

if choice == '1':  
    print(f"The result is: {num1 + num2}")  
elif choice == '2':  
    print(f"The result is: {num1 - num2}")  
elif choice == '3':  
    print(f"The result is: {num1 * num2}")  
elif choice == '4':  
    if num2 != 0:  
        print(f"The result is: {num1 / num2}")  
    else:  
        print("Division by zero is not allowed.")  
else:  
    print("Invalid choice.")  

Practice Exercises

To solidify what you’ve learned, try these additional exercises:

1. Even or Odd Checker: Create a program that takes a number as input and prints whether it is even or odd.

num = int(input("Enter a number: "))  
if num % 2 == 0:  
    print(f"{num} is even.")  
else:  
    print(f"{num} is odd.") 

1. Extended Calculator: Enhance the basic calculator by adding support for modulus and exponentiation. For example:

print("5. Modulus")  
print("6. Exponentiation")  

if choice == '5':  
    print(f"The result is: {num1 % num2}")  
elif choice == '6':  
    print(f"The result is: {num1 ** num2}")

Conclusion

Understanding Python’s syntax, operators, and input/output operations is the first step toward becoming a confident programmer. With these foundations in place, you’re ready to tackle more advanced topics and projects.

Give the Practice Exercises a try, and let us know how you did in the comments below! We’d love to see your results and help you if you get stuck.