Python Basics Overview

Overview

This lecture provides a beginner-friendly introduction to Python programming, covering installation, basic syntax, variables, data types, operators, control structures, collections, loops, functions, and project ideas.

Getting Started with Python

• Download Python from python.org and install it on your system.
• Use IDEs like PyCharm or pythonanywhere.com for writing code.
• The first code prints text using print("Hello World").
• Strings can be written in single or double quotes.

Basic Syntax and Variables

• Comments are written using # and are ignored by Python.
• Variables store data and are assigned with =.
• Variable names should be descriptive and follow Python naming rules.
• Variable types include string, integer, float, and boolean.
• Variables can change values after assignment.

Taking Input and Type Conversion

• Use input() to get user data; input is always a string.
• Convert input to int (int()), float (float()), or bool (bool()) when needed.
• Concatenate strings using +, e.g., "Hello " + name.

Data Types and Operations

• Integer: whole numbers (e.g., 24); Float: decimals (e.g., 24.0).
• Boolean: True or False values (case sensitive).
• String methods include .upper(), .lower(), .find(), .replace().
• Data type conversion is needed for arithmetic with inputs.

Operators

• Arithmetic: + (add), - (subtract), * (multiply), / (divide), // (integer divide), % (modulo), ** (power).
• Comparison: >, <, >=, <=, ==, !=.
• Logical: and, or, not.***

Control Structures

• Use if, elif, else for conditional logic.
• Code blocks require indentation (typically 4 spaces).
• Nested conditions determine code flow.

Loops

• while loops execute while a condition is true; remember to update loop variables.
• for loops iterate over sequences (like range() or lists).
• Use break to exit loops and continue to skip to the next iteration.

Collections: List, Tuple, Set, Dictionary

• List: ordered, mutable collection ([95, 98, 97]); supports indexing and slicing.
• Tuple: ordered, immutable collection ((95, 98, 97)).
• Set: unordered, unique elements ({95, 98, 97}).
• Dictionary: key-value pairs ({"english":95, "chemistry":98}).

Functions

• Define functions with def function_name(parameters):.
• Functions can have default parameter values.
• Use return to provide output from a function.
• Use modules (like math) with import statements.

Project Ideas and Practice

• Mini-project: build a calculator using input, operators, and conditionals.
• Practice using loops to print patterns and process collections.

Key Terms & Definitions

• Variable — a named location in memory to store data.
• String — a sequence of characters (text).
• Boolean — a type with values True or False.
• List — an ordered, mutable collection of items.
• Tuple — an ordered, immutable collection of items.
• Set — an unordered collection of unique items.
• Dictionary — a collection of key-value pairs.
• Function — a reusable block of code defined with def.
• Module — a file containing Python definitions and statements.

Action Items / Next Steps

• Practice defining variables and using basic data types.
• Try both input and output operations.
• Complete provided exercises on variables and input.
• Write a calculator and pattern-printing program.
• Review list, tuple, set, and dictionary operations.
• Explore the math module and try writing your own functions.