Operators & Expressions

Overview

Operators are symbols that let you perform math, compare values, and combine logical conditions.

Learning Objectives

• Use mathematical operators (+, -, *, /, //, %.
• Compare values using equality and inequality symbols.
• Combine multiple checks using and, or, and not.

Concept Explanation

Operators carry out operations. Math symbols include standard arithmetic along with // (floor division, which discards decimals) and % (modulo, which returns the remainder of a division). Comparison operators check equality (==) or inequality (!=). Logical operators let you join checks together.

Code Examples

Example 1 — Basics

This example introduces the fundamental syntax and concepts.

addition = 5 + 3
is_greater = 10 > 7
both_true = True and False

Example 2 — Everyday Usage

This example demonstrates a realistic scenario handling business parameters.

# Calculate leftover items
total_apples = 13
basket_capacity = 4
baskets_filled = total_apples // basket_capacity
leftovers = total_apples % basket_capacity
print('Baskets:', baskets_filled, 'Leftovers:', leftovers)

Example 3 — Advanced Example

This example shows clean, production-grade code structure following senior development standards.

# Verify user permission and system access
user_role = 'admin'
is_logged_in = True
has_permission = is_logged_in and (user_role == 'admin' or user_role == 'manager')
print('Access allowed:', has_permission)

Visual Flow

The following execution flow represents the step-by-step evaluation inside the interpreter:

Evaluate Left Expression → Check Logical operator → Skip Right if Left suffices (Short-Circuit) → Return final value

Common Mistakes

Review these common pitfalls when working with this topic:

• Using a single equals sign (=) for checking equality instead of double equals (==).
• Confusing floor division // with regular division /.
• Forgetting parentheses when mixing 'and' with 'or' in complex expressions.
• Using the identity check 'is' when you only want to compare values for equality.

Best Practices

Enforce these Pythonic best practices in your codebase:

if is_ready == True: # Redundant check

if is_ready: # Clean boolean check

Performance Notes

Keep these optimization guidelines in mind for performance-sensitive hotpaths:

• Logical operators (and, or) evaluate lazily (short-circuiting), stopping early if the first check satisfies the expression.

Quick Revision

Use these key summaries for last-minute revision:

• +, -, *, / perform standard math operations.
• Floor division (//) removes decimal fractional parts.
• Modulo (%) yields the remainder of a division.
• == checks if values are equal; != checks inequality.
• and/or operators stop checking early if the outcome is already clear.