Fundamentals of Programming with Python

Introduction

• Presenter: Kevin
• Audience: Beginners with no programming background
• Goals: Learn basics of Python step-by-step until you can write and run your own source code.

Why Learn Programming?

• Ubiquity of Programming: Apps on phone, software on PC – all are products of programming.
• Benefits: Realize ideas through a series of steps that a computer can execute.
• Example Applications: Games, workplace applications, scientific analyses.

Why Python?

• Popularity: High demand; voted as the most desired language by Kevin's audience.
• Usability: Easy to use and understand with concise syntax.
• Versatility: Suitable for web apps, internal tools, games, scientific analysis.
• Transferable Skills: Concepts learned in Python apply to other languages.

Setting Up Python

1. Check Installation: python --version in Command Prompt.
2. Install Python: If not found, download from python.org
3. Installation Tips: Check 'add Python to PATH' during setup.
4. Verify Installation: python --version should now show the version.

Writing and Running Python Code

1. Python Terminal: Use Python terminal to execute code (python in Command Prompt).
2. Basic Syntax: Correct syntax needed, e.g., 1 + 2, print("Hello World").
3. Exit Python Terminal: Type exit().
4. Text Editor: Use Notepad or more efficient IDEs (Integrated Development Environments).

IDE Installation

• Visual Studio Code: Recommended, free, supports all major OS.
• Install Extensions: Python extension.
• Set Interpreter: Ctrl+Shift+P → Python: Select Interpreter → Choose installed version.

Variables and Data Types

1. Creating Variables:
   • Syntax: variable_name = value
   • Must follow rules (no spaces, starts with a letter, etc.)
2. Example:

   red_bucket = "Kevin"
   red_bucket = 10  # Overwrites 'Kevin'
   

3. Type Checking: type(variable) returns the type (e.g., str, int).
4. Deleting Variables: del variable_name
5. User Input:

   var = input("Message")
   

Operators

1. Arithmetic Operators: +, -, *, /.
2. Order of Operations: PEMDAS (Parentheses, Exponents, Multiplication/Division, Addition/Subtraction).
3. Special Operators:
   • Exponentiation: **
   • Floor Division: //
   • Modulus: %

Strings

1. Creating Strings: Enclosed in double or single quotes ("Hello" or 'Hello').
2. Handling Quotes: Use alternate quote styles to handle quotes within strings.
3. Whitespace: Space and newline characters do not affect code execution.

Comments

1. Single-Line Comment: Precede with #.
2. Multi-Line Comment: Use ''' or """.
3. Usage: Explain code or temporarily disable code.

Conditional Statements (if, elif, else)

1. Syntax:

   if condition:
       # Code block
   elif another_condition:
       # Code block
   else:
       # Code block
   

2. Example: Check age for school level.

   if age < 5:
       print("Preschool")
   elif age == 5:
       print("Kindergarten")
   else:
       print("Other class")
   

Functions

1. Defining a Function:

   def function_name(parameters):
       # Code block
   

2. Example:

   def print_hello():
       print("Hello")
   

3. Calling a Function:

   print_hello()
   

4. Parameters and Return Values:

   def add(a, b):
       return a + b
   result = add(3, 4)  # Returns 7
   

5. Using Functions with Conditional Logic: Functions can include if-statements.

Loops

1. While Loop:

   while condition:
       # Code block
   

   Example:

   x = 0
   while x < 5:
       print(x)
       x += 1
   

2. For Loop:

   for variable in iterable:
       # Code block
   

   Example:

   for x in range(5, 10):
       print(x)
   

Importing Libraries

1. Syntax: import library_name
2. Example:

   import math
   print(math.pi)  # Prints value of Pi
   

Error Handling

1. Syntax Errors: Usually due to incorrect syntax. Fix by reviewing code.
2. Runtime Errors: Occur during code execution (e.g., division by zero).
3. Semantic Errors: Code runs but not as expected due to logical errors.

Conclusion

• Covered basics of Python: Variables, operators, strings, comments, conditionals, loops, functions, importing libraries, and basic error handling.
• Practice by exploring further and trying out more advanced projects.